Download Atoms and Elements

Atoms and Elements
Experiencing Atoms
• Atoms are incredibly_______________, yet they ___________________ everything.
• Atoms are the ______________________________of elements.
• _______________of the atoms determine the __________________ of the elements.
The Language of Chemistry
• CHEMICAL ELEMENTS  pure substances that cannot be ______________________________by
____________________ means to other substances.
Experiencing Atoms
• There are about ________________elements found in nature.
 Over _________________have been made in laboratories.
Each has its own, unique kind of____________________.
 They have different_______________________________.
 Therefore they have different__________________________________.
The Divisibility of Matter
• ______________________________
 For any two points, there is always a point between.
• _______________________________
 Upon division, eventually a particle is reached which can no longer be divided.
•
Nothing exists except atoms and empty space; everything else is opinion.” - Democritus 460–
370 B.C.
Atomic Theory of Matter
The theory that _____________________are the fundamental building blocks of
______________reemerged in the early 19th century, championed by_________________.
Dalton’s Atomic Theory
John Dalton (1766-1844) proposed an ___________________________
While this theory was __________completely correct, it revolutionized how chemists looked at
matter and brought about chemistry as we know it ___________________instead of alchemy
Thus, it’s an important __________________in the history of science.
Dalton’s Atomic Theory
1. Each Element is composed of tiny, indestructible particles called________________.
 Tiny, hard, indivisible, spheres.
2. All _________________of an element are_______________________________.
 They have the same mass, volume, and other
_____________________________________________.
 Every carbon atom is identical to every other carbon atom.
1. They have the same chemical and physical properties.
3. However, carbon atoms are ____________________from sulfur atoms. (Atoms of one
element are different from atoms of another element.)
1. They have ________________________chemical and physical properties.
4. Atoms combine in simple, __________________ ratios to form molecules of compounds.
 Because atoms are unbreakable, they must combine as whole atoms.
 The ___________of the atom determines the ___________in which it combines.
 Each molecule of a compound contains the exact ____________________and
___________________of atoms.
1.
Law of Constant Composition
Atoms combine in certain whole-number ratios
2. Chemical formulas
5. In a chemical reaction, atoms are merely
______________________to form new compounds; they
are not ___________________________________into
atoms of any other elements.
Dalton’s Atomic Theory Summary
1. matter is composed of, indivisible particles
(_______________________)
2. all atoms of a particular element are____________
3. different elements have_______________ atoms
4. atoms combine in certain ______________________________ ratios
5. In a chemical reaction, atoms are merely __________________to form new compounds;
they are not created, destroyed, or changed into atoms of any other elements.
Problems with Dalton’s Atomic Theory?
1. matter is composed of indivisible particles
_________________________________, but only in a nuclear reaction
2. all atoms of a particular element are identical
Does Not Account for ____________________(atoms of the same element but a
different mass due to a different number of neutrons)!
3. different elements have different atoms
_______________________
4. atoms combine in certain whole-number ratios
YES! Called the________________________________________________
5. In a chemical reaction, atoms are merely rearranged to form new compounds; they are not
created, destroyed, or changed into atoms of any other elements.
______ (NUCLEAR reactions can change atoms of one element into a different element)
The Atom
An atom consists of a
•
__________________________
 (of __________________and___________________________)
•
______________________________in space about the nucleus.
An ____________________ is the smallest particle of an element that has the chemical
properties of the element.
Other Subatomic Particles
•
_____________________
 component of protons & neutrons
 ___________types
__________quarks = 1 proton or 1 neutron
ATOM COMPOSITION
The atom is mostly____________________________
•
protons and neutrons in the___________________________.
•
the number of electrons is _____________________to the number of protons.
•
electrons in space ___________________________the nucleus.
•
_______________________________. One teaspoon of water has 3 times as many
atoms as the Atlantic Ocean has teaspoons of water.
The Modern Atom
•
We know atoms are composed of three main pieces—___________________________.
•
The _______________________________contains protons and neutrons.
•
The nucleus is only about ________________________ in diameter.
•
The electrons move ___________the nucleus with an average distance of about 10-8 cm.
 Therefore, the radius of the ______________is about _______________times
________________________ than the radius of the nucleus.
Sizes of Atoms
•
Using compositions of compounds and assumed formulas, Dalton was able to determine
the______________________________ masses of the atoms.
 Dalton based his scale on H = 1 amu.
 We now base it on ________________= 12 amu exactly.
 Amu =_________________________________________
•
Absolute sizes of atoms:
 Mass of H atom=_____________________________________
 Volume of H atom = 2.1 x 10-25cm3.
ATOMIC COMPOSITION
• Protons (p+)

(______________) positive electrical charge

mass = 1.672623 x 10-24 g

relative mass = 1.007 atomic mass units (_________________)
____________________________________
• Electrons (e-)

(__________________) negative electrical charge

relative mass = 0.0005 amu
________________________________________
• Neutrons (no)

____________________ electrical charge

mass = 1.009 amu
_______________________________________
Atomic Number, Z
All atoms of the ____________________have the ___________________________in the
nucleus. This is represented by the letter Z.
______________________________________
Mass Number, A
• _________with 6 protons and 6 neutrons is the _____________= 12 atomic mass units
• _______________________(A) = # protons + # neutrons
• ___________on the periodic table…(That is the AVERAGE atomic mass on the table)
• A boron atom can have _____________________________= 10 amu
The Nature of Electrical Charge
• Electrical charge is a fundamental property of______________ and_______________.
• Positively and negatively charged objects _________________________each other.
• Like charged objects ____________________each other.
 + to +, or  to .
• When a proton and electron are_____________, the result is a _____________charge.
 Because they have ____________________________amounts of charge.
Some Notes on Charges
•
•
•
•
There are __________________kinds of charges, called positive and negative.
_________________________charges attract.
 + attracted to –.
_____________________________charges repel.
 + repels +.
 – repels –.
To be neutral, something must have ______________________________ or
____________________________________charges.
Maintaining and Restoring Charge Balance
Matter is normally charge-neutral. When it is disturbed it is quickly rebalanced.
Subatomic
Mass
Mass
Location
particle
g
amu
in atom
Proton
1.67262
Charge Symbol
p, p+, H+
x 10-24
Electron
0.00091
e, e-
x 10-24
Neutron
1.67493
n, n0
x 10-24
Practice—An Atom Has 20 Protons. Determine if Each of the Following Statements Is
True or False?
• If it is a neutral atom, it will have 20 electrons.____________________
• If it also has 20 neutrons, its mass will be approximately 40 amu.__________________
• If it has 18 electrons, it will have a net 2 charge._______________________
Elements
• Each element has a _________________________number of protons in its nucleus.
 All carbon atoms have 6 protons in their nuclei.
The ______________________in the nucleus of an atom is called the atomic number.
 ________is the short-hand designation for the________________________.
 Because each element’s atoms have a unique number of protons, each element can
be________________________ by its atomic number.
 The elements are arranged on the Periodic Table in order of
their___________________________.
• Each element has a unique_________________________________.
 The symbol is either ________________________letters
 One capital letter or one capital letter + one lower case letter.
Structure of the Nucleus
•
•
•
Soddy discovered that the same element could have atoms with__________________,
which he called_______________________.
 There are two isotopes of chlorine found in nature, one that has a mass of about
35 amu and another that weighs about 37 amu.
The observed mass is a ____________________of the weights of _____________the
naturally occurring atoms.
 The atomic mass of chlorine is 35.45 amu.
Isotopes
• Atoms of the _________________(same Z) but __________________________(A).
• Boron-10 (10B) has 5 p and 5 n
Boron-11 (11B) has 5 p and 6 n
All isotopes of an element are _________________________________
• Undergo the exact ____________________chemical reactions.
• All isotopes of an element have the ________________________________________
• Isotopes of an element have_____________________________.
• Isotopes of an element have _________________________________________
• Isotopes are identified by their____________________________ (A)
• Protons + neutrons.
• Atomic Number.
• _________________________
• Z
• Mass Number
• ____________________________
• Whole number
• A
• Percent natural abundance =_____________________ amount found in a sample.
Atomic Symbols
 Show the name of the element, a hyphen, and the mass number in__________________
sodium-23
 Show the mass number and atomic number in _________________________________
DRAW THE SYMBOL_____________________________
Three Isotopes of Hydrogen
Write both the hyphen notation and nuclear symbol form for each isotope of hydrogen.
•
Isotopes?
Which of the following represent isotopes of the same element? Which element?
234
X
92
234
93
X
235
238
X
92
_________________________________
X
92
Counting Protons, Neutrons, & Electrons
• Protons: Atomic Number (___________________________)
Neutrons: Mass Number _________________the number of protons (mass number is
protons and neutrons because the mass of electrons is negligible)
• Electrons:
 If it’s an___________, the protons and electrons must be the _____________so
that it is has a net charge of zero (equal numbers of + and -)
 If it does NOT have an equal number of electrons, it is not an atom, it is
an________________.
 For each negative charge,___________________________________.
 For each positive charge, ________________________________.
(Don’t add a proton!!! That changes the element!)
•
Learning Check – Counting
Naturally occurring carbon consists of three isotopes, 12C, 13C, and
protons, neutrons, and electrons in each of these carbon atoms.
12
13
C
6
14
C
6
14
C. State the number of
C
6
#p+ _________
_________
_________
o
#n _________
_________
_________
#e- _________
_________
_________
Learning Check
An atom has 14 protons and 20 neutrons. (Circle the correct answer)
A.
Its atomic number is
1) 14
2) 16
3) 34
B. Its mass number is
1) 14
2) 16
3) 34
C. The element is
1) Si
2) Ca
3) Se
D.
Another isotope of this element is
1) 34X
2) 34X
3) 36X
16
14
14
Example 4.8—How Many Protons and Neutrons Are in an Atom of
52
24
Cr ?
Practice—Complete the Following Table
Atomic
Mass
Number Number
Number Number
of
of
protons electrons
Number
of
neutrons
Calcium-40
_______________________________________________________
Carbon-13
_______________________________________________________
+3
Aluminum-27_______________________________________________________
Mass Number Is Not the Same as Atomic Mass
•
The atomic mass is an _____________________ number determined from all naturally
occurring ____________________________.
•
The mass number refers to the number of ___________________in ________isotope.
 Natural or man-made.
AVERAGE ATOMIC MASS
•
Because of the existence of isotopes, the mass of a collection of atoms has
an___________________________________________.
•
Boron is 20%
•
For boron atomic mass_________________________________________________
10
B and 80% 11B. That is, 11B is 80 percent abundant on earth.
Isotopes & Average Atomic Mass
•
Because of the existence of isotopes, the mass of a collection of atoms has an average
value.
•
6
•
28
Li = 7.5% abundant and 7Li = 92.5% Avg. Atomic mass of Li = ____________________
Si = 92.23%,
29
Si = 4.67%,
30
Si = 3.10%
 Avg. Atomic mass of Si = ___________________________________________
Example 4.9─Ga-69 with abundance of 60.11% and Ga-71 with abundance of 39.89%. Calculate
the Atomic Mass of Gallium.
Given:
Find:
Solution:
Practice—If Copper Is 69.17% Cu-63 and the Rest Cu-65. Find Copper’s Atomic Mass.
Given:
Find:
Solution:
The Language of Chemistry
•
The elements, their names, and symbols are given on the_________________________
Mendeleev
•
Ordered elements by_______________________________.
•
Saw a repeating pattern of________________________________.
•
____________________________—When the elements are arranged in order of
increasing relative mass, certain sets of properties recur periodically?
•
Used pattern to ________________________________of undiscovered elements.
•
Where atomic mass order did not fit other properties, he reordered by still other
properties._______________________________________
•
Mendeleev's Predictions for Ekasilicon (Germanium)
Property
Atomic
mass
Color
Silicon’s
props
28
Tin’s
props
118
Gray
Density
2.32
White
metal
7.28
Reaction
with acid
and base
Resists
acid,
reacts
base
SiO2
Reacts
acid,
resists
base
SnO2
Oxide
Predicted Measured
value
value
Glenn Seaborg (1912-1999 )
• Discovered _______________ new elements.
• Only _______________________________ person for whom an element was named.
Review
• What is the atomic number of boron, B?___________________________________
• What is the atomic mass of silicon, Si?____________________________________
• How many protons does a chlorine atom have?_______________________________
• How many electrons does a neutral neon atom have? __________________________
• Will an atom with 6 protons, 6 neutrons, and 6 electrons be electrically neutral?______
• Will an atom with 27 protons, 32 neutrons, and 27 electrons be electrically neutral?
• Will a Na atom with 10 electrons be electrically neutral?________________________
Use the table above to label areas of the periodic table as we discuss them in the PP lecture.
Metals
• __________________________at room temperature, except Hg.
• _______________________________surface.
 Shiny
• Conduct________________________________.
• Conduct__________________________________.
• ________________________________________.
 Can be shaped.
• ________________________________________.
 Drawn or pulled into wires.
• _________________________and form ________________________in reactions.
• About __________________________________of the elements are metals.
• __________________________________________________on the table.
Nonmetals
• Found in all_____________________________________.
• Poor conductors of_______________________________.
• Poor conductors of_______________________________.
• Solids are______________________________________.
• ________________________________in reactions to become_________________.
• ______________________________on the table.
Except H.
Metalloids
• Show some properties of ______________ and some of _____________________.
• Also known as _______________________________________
Properties of Silicon:
 Shiny
Conducts electricity
Does not conduct heat well
Brittle
Practice—Classify Each Element as Metal, Nonmetal, or Metalloid.
• Xenon, Xe ________________________
• Tungsten, W ________________________
• Bromine, Br ________________________
• Arsenic, As ________________________
• Cerium, Ce ________________________
The Modern Periodic Table
• Elements with __________chemical and physical properties are in the_____________.
• Columns are called _________________or__________________________.
 Designated by a______________and ___________________at top.
LABEL YOUR PERIODIC TABLE ABOVE WITH THE FAMILY NAMES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The Modern Periodic Table
• Rows are called_____________________________________.
• Each period shows the______________ of properties ___________in the next period.
• Main group = _____________________________________= “A” groups.
• Transition elements = ___________________________________ groups. All metals.
• Bottom rows = _____________________________________= rare earth elements.
• Metals
Really belong in periods 6 and 7.
Charged Atoms
• The number of _____________________________determines the element.
 All sodium atoms have 11 protons in the nucleus.
• In a ______________________change, the number of protons in the nucleus of the
atom________________________________________.
 No _______________________________during a chemical change!!
 During radioactive and nuclear changes, atoms do transmute.
• Atoms in a compound are often electrically charged, these are called_______________.
Valence Electrons and Ion Charge
• The ________________electrons in an atom are called the _____________________.
• Metals form ___________by losing their valence electrons to get the same number of
electrons as the _________________noble gas.
 Li loses one to be like He-----Li+ = 2 e = He
 Al loses three to be like Ne----- Al3+ = 10 e = Ne
• Cations are pawsitive.
• The letter t in cation looks like a positive plus sign +: ca+ion
Valence Electrons and Ion Charge
• Nonmetals form ___________________by gaining electrons to have the same number
of electrons as the _____________________________noble gas.
 Cl gains one electron to be like Ar-----Cl = 18 e = Ar
 Se gains two to be like Kr-------Se2 = 36 e = Kr
Ions
• Atoms acquire a charge by _________________________________electrons.
 _________________________________!
• Ion charge =___________________________________________________.
• Ions with a _____________________________charge are called cations.
 More protons than electrons.
 Form by ______________________________electrons.
• Ions with a __________________________________charge are called anions.
 More electrons than protons.
 Form by ___________________________________electrons.
• Chemically, ions are _______________________________than the neutral atoms.
 Because they have a___________________________________________.
IONS
• ___________________are atoms or groups of atoms with a positive or negative charge.
• __________________an electron from an atom gives a CATION with a positive charge
• ___________________an electron to an atom gives an ANION with a negative charge.
•
To tell the difference between an atom and an ion, look to see if there is a
_____________ in the ___________________! Examples: Na+ Ca+2 I- O-2___________
Na
Ca
I
O ______
Ion Charge and the Periodic Table
• The charge on an ion can often be determined from an elements _________________on
the periodic table.
• Metals are always positive ions, nonmetals are negative ions.
• For many main group metals:_____________________________________________.
• For nonmetals:_______________________________________________________.
Atomic Structures of Ions
•
Nonmetals form anions.
•
For each negative charge, the ion has _______________electron than the neutral atom.
 F = 9 p+ and 9 e; F─ = 9 p+ and 10 e.
 P = 15 p+ and 15 e; P3─ = 15 p+ and 18 e.
•
Anions are named by changing the _______________of the name to_______________.
fluorine
F + 1e  F─ fluoride ion
oxygen
O + 2e  O2─
oxide ion
•
The charge on an anion can often be determined from the _____________________on
the periodic table.
•
Group 7A  1, Group 6A  2.
•
Metals form cations.
•
For each positive charge the ion has ________________electron than the neutral atom.
HOW??????_____________________________
 Na atom = 11 p+ and 11 e; Na+ ion = 11 p+ and 10 e.
 Ca atom = 20 p+ and 20 e; Ca2+ ion = 20 p+ and 18 e.
•
•
Cations are named _______________as the________________.
sodium
Na  Na+ + 1e
sodium ion
calcium
Ca  Ca2+ + 2e
calcium ion
The charge on a cation can often be determined from the _____________________on
the periodic table.
 Group 1A  1+, Group 2A  2+, (Al, Ga, In)  3+.
HOW???????_____________________________________________________
Forming Cations & Anions A CATION forms when an atom loses one or more electrons.
An ANION forms when an atom gains one or more electrons.
PREDICTING ION CHARGES metals lose electrons ---> cations
nonmetals gain electrons --->anions
Learning Check – Counting State the number of protons, neutrons, and electrons in each of these ions.
39
K+
19
16
O
-2
8
41
Ca
+2
20
#p+
_________
_________
__________
#no
_________
_________
__________
#e-
_________
_________
__________
Write the nuclear symbol form for the following atoms or ions:
A. 8 p+, 8 n, 8 e-
____________________________________
B. 17p+, 20n, 17e-
____________________________________
C. 47p+, 60 n, 46 e-
____________________________________
Label the charges for each column
By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.
Example 4.5—Find the Number of Protons and Electrons in Ca2+.
Practice—Fill in the Table.
Ion
Cl-1
K+1
S-2
Sr+2
p+
e-