Download Particulate View of Matter

Chapter 6.1
• What are atoms?
• How are the particles that make up
atoms diagrammed?
• What are the similarities between
covalent and ionic bonds
• What are van der Waals forces?

All the organisms you study in Biology
are made up of matter.

Atoms are the building blocks of matter.

Nucleus – the dense center of the atom that
contains the protons and neutrons

Electron cloud – area around the nucleus
where the electrons exist.

An atom is mostly empty space.

There are 3 basic subatomic particles.
Location
Charge
Mass
electron
proton
neutron
Electron
cloud
nucleus
nucleus
-
+
neutral
0 amu
1 amu
1 amu

A Boy and His Atom – IBM

Bill Nye – Atoms

Matter that is made up of only one kind of
atom is known as an element.

Elements:
 Pure substance – cannot be broken down into
other substances
 Composed of only one kind of atom.
▪ Oxygen is only composed of oxygen atoms.
 92 different elements occur naturally
MUST know the first 40 elements!
Periodic Table Game



Mendeleev – discoverer of the periodic law
and thus the periodic table.
He arranged the periodic table looking for
trends or patterns (periodic).
Has been changed over time .

113 - Nihonium and symbol Nh
 Nihon is 1 of the2 ways to say “Japan” in Japanese
 Means “Land of the Rising Sun”

115 - Moscovium and symbol Mc
 Joint Institute for Nuclear Research, Dubna (Russia)

117 - Tennessine and symbol Ts
 Vanderbilt University (USA) and Lawrence Livermore
National Laboratory (USA)


118 - Oganesson and symbol Og
honoring a scientist and recognizes Professor
Yuri Oganessian (born 1933) for his pioneering
contributions.

Elements are the most basic level, made up
of all one type of atom.
 Identified by chemical symbol
 Organized on the Periodic Table of Elements
i.
ii.
iii.
First letter always capital
Second letter (if present) always lower case
Some symbols derived from Latin names:
a.
b.
c.
Sodium - Na - Natrium
Iron - Fe - Ferium (blacksmiths called farriers)
Lead - Pb - Plumbum (derived by a plumber)

Atomic Number
 The number of protons in the nucleus
 Unique to each element
 Smaller # on periodic chart
 Protons and neutrons have a mass of 1 atomic
mass unit
 Electrons are so small they are not counted in the
mass of the atom
 Number of electrons equals number of protons

Mass number
 Also referred to as atomic mass
 The number of protons and neutrons added
together
 The number of neutrons in an atom can be
calculated by subtracting the # of protons (atomic
#) from the mass number
mass # - atomic # = # of neutrons

Electrons = atomic number

Protons = atomic number

Neutrons = mass # - atomic #

Periods (Horizontal)
 Number of electron shells

Groups (Vertical)
 Determine Valence Electrons

Oxidation numbers:
 Show the number of bonds needed for full
valence shell




outermost electrons
important in bonding.
Use dots or x’s to represent valence electrons.
Also called Lewis Structures – electron dot
Use Group numbers (oxidation) to balance compounds
+1
0
+2
+3 +/-4 -3
-2
-1

The following is the order of filling (single
first, then double):
1. What is the basic unit of life?
A.
B.
C.
D.
Atom
Element
Cells
Organisms
2. How many electrons does Carbon have?
A.
B.
C.
D.
2
4
6
8
3. How is the neutron number calculated?
A. Protons = neutrons
B. Protons + atomic mass
C. Electrons = neutrons
D. Atomic mass - protons
4. Carbon and Silicon both:
A.
B.
C.
D.
Have the same number of total electrons
Have the same number of outer electrons
Are in the same period
Have the same number of protons
5. How many valence electrons does an atom of
Nitrogen have?
A. 3
B. 4
C. 5
D. 6
6. When oxygen forms a compound, what will
happen to the electrons?
A. Oxygen will Lose 2 electrons
B. Oxygen will Gain 6 electrons
C. Oxygen will Gain 2 electrons
D. Oxygen will Lose 6 electrons
Isotopes

Atoms of the same element that have:
 same number of protons and electrons
 different number of neutrons



Changing the number of neutrons in an
atom does not affect the charge, but does
affect the stability.
When a nucleus breaks apart, it gives off
radiation that can be detected and used
for many applications.
Isotopes that give off radiation are called
radioactive isotopes.

Carbon-11 or 11C
 radioactive isotope of carbon that decays to boron-11

Carbon-12 or 12C
 Stable, most abundant, found in living organisms

Carbon-13 or 13C
 Stable, 2nd most abundant, used in medical diagnostic
tests

Carbon-14 or 14C

14C
is an unstable, radioactive isotope; carbon dating
Element
 Pure substance – cannot be broken down into other substances
 Mixture
 Two or more physically separable components
 Not bonded together
 Compound
 Pure substance formed when two or more different elements
combine.
 Cannot be broken down into simpler compounds or elements by
physical means but can be broken down by chemical means.
 Molecule
 Two or more atoms chemically bonded together by sharing
electrons

The force that holds
substances together
 The electrons of an atom
are responsible for forming
chemical bonds.
 Electrons travel around the
nucleus of an atom in areas
called energy levels.
 Atoms become more stable
by losing electrons or
attracting electrons from
other atoms.

•
When electrons
are shared.
• A molecule is a
compound in
which the atoms
are held together
by covalent
bonds.

Molecules
 Two or more atoms chemically bonded together
by sharing electrons
 Diatomic molecules are all the same atom
▪ GEN – u – INE Diatomics
▪ Hydrogen, Oxygen, Nitrogen, Fluorine, Chlorine,
Bromine and Iodine
chlorine atom
chlorine atom
chlorine molecule
 Nonpolar:
▪ Share equally
▪ Two of the same element or in the same group
 Polar:
▪ Still share, but a slight charge
▪ Water
▪ Carbon with Group 6 or 7



An atom that has lost or gained one or
more electrons is an ion.
Ions carry an electric charge.
An ionic bond is an electrical attraction
between two oppositely charged atoms.

Ionic Bonds: (Cation / Anion) Gain or Lose electrons
 Usually +1, +2 or -1, -2 (sometimes +/-3)
 Opposite ends of the periodic table
▪ Metals and nonmentals
 Cation listed first (positive charge)
 Anion listed second (negative charge)

Some atoms tend to donate or accept electrons
more easily than other atoms.
• The elements identified as metals tend to
donate electrons.
• The elements identified as nonmetals tend to
accept electrons.
• Most ionic compounds
• dissolve in water
• are crystalline at room temperature
• have higher melting points than compounds formed
by covalent bonds.

Series of symbols and subscript numbers that
represent different chemical substances.
C6H12O6


Letters represent chemical symbol of the
element
Numbers tell how many atoms of each
element are present in the molecule

Subscripts tell you the ratio of different
atoms in a compound
H2O
• tells us there are 2 hydrogen atoms
• If there is no subscript, there is just one atom.
(just like coefficients in algebra)
▪ There is just one oxygen in water

Parentheses are used around groups of
atoms that act as one unit (polyatomic ions)
Ca(OH)2
Ba(NO3)2

1) NaOH
- Na is 1 because there is no subscript
- O is 1 because there is no subscript
- H is 1 because there is no subscript.
- There are three total because of 1 + 1 + 1 = 3

2) MgCl2
- Mg is 1 because there is no subscript
- Cl is 2 because that is the subscript
- There are 3 total because of 1 + 2 = 3
Balance the following compound:
Potassium and Oxygen
A. KO
B. K2O
C. K2O2
D. KO2
Balance the following compound:
Aluminum and Oxygen
A. AlO
B. Al2O
C. Al2O2
D. Al2O3



Attractions between molecules.
When molecules come close together, the
attractive forces between slightly positive
and negative regions pull on the
molecules and hold them together.
The strength of the attraction depends on:
 the size of the molecule
 its shape
 its ability to attract electrons.


The slightly positive and slightly negative
charges around the water molecule are
attracted to the opposite charge of other
nearby water molecules.
van der Waals forces are responsible for
water droplet formation and surface
tension.