Download Block 1 and 2 The Nature of Matter

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Unit 2: Biochemistry – ATOMS!
The Nature of Matter!
No Bellringer Today!
The Basics
• Matter: anything that has mass and takes
up space.
• Atom: The basic unit of matter
• Element: A pure substance that consists
of entirely one atom.
• Compound: a substance formed by the
chemical combination of two or more
elements.
Subatomic particles
• Proton: (+) Positively charged particle in
the nucleus of the atom.
• Neutron: (0) A particle in the nucleus that
has no charge.
• Electron: (-) negatively charged particle
that is in constant motion outside the
nucleus (in the electron shell).
Sub-Atomic Math
Sub-Atomic Particle
Mass
Charge
Proton
Neutron
Electron
1
1
0
+1
0
-1
Atomic Number
The Atom
Helium
2
Element Symbol
He
Helium
Element Name
4
Atomic Mass
Each element is made of atoms. The elements are currently arranged by
atomic number.
I spent my time arranging the
elements and came up with
the
Periodic Table of Elements in
1865.
Mendeleev
You can determine the number of protons, neutrons,
and electrons using the Periodic table.
= number of protons
Atomic
Number = number of electrons
6
C
Carbon
12
Element Symbol
Element Name
Atomic Mass = number of protons + number of neutrons
Let’s Try It!
The Atom Helium
Atomic Number
rotons= 2
Electrons= 2
Neutrons= 4 - 2
Helium has two
protons, two
electrons, two
neutrons
=2
2
He
Helium
4
Element Symbol
Element Name
Atomic Mass
The Atom Helium
Nucleus : Contains Protons and Neutrons
Shell contains
Electrons
e
He P:2
N:2
e
Electron Shell : Energy Levels
Energy Levels: in electron cloud
1st Energy Level = Max. of 2 electrons
2nd Energy Level = Max. of 8 electrons
3rd Energy Level = Max. of 8 electrons
4th Energy Level = Max. of 18 electrons
Electron in 1st
energy level
Electron in 2nd
energy level
Electron in 3rd
energy level
Nucleus
Valence Electrons
Valence electrons: electrons in the outer most
energy level
= valence
electrons- 8 red
dots in outer
energy level
Niels Bohr
e
e
e
P:5
B N:6
e
e
Bohr Model
Drawing an atom model…
- Begin with the element and determine how
many protons, neutrons, and electrons there
are.
Boron: Atomic Number 5
Atomic Mass 11
Protons: 5
Neutrons: 6
Electrons: 5
P:5
go inside nucleus
go in electron shell
B N:6
The Nucleus contains 5
protons and 6 neutrons
P:5
B N:6
There are two electrons on the
first energy level. This energy
level is full, so we go to the next
energy level
After placing 2 electrons
on the first energy level,
Boron still has 3 more
electrons. These
electrons are put on the
2nd energy level.
Valence Electrons: There are 3 valence electrons. To
determine this, we look at the outer most energy level
(in this case the 2nd level). Then we count the number
of electrons. There are 3 electrons on the 2nd energy
level.
Boron
REMEMBER…
ALWAYS FILL THE INNER
ENERGY LEVELS FIRST!!! START
ST
WITH THE 1 ENERGY LEVEL!
Draw an atom of…
Sodium: Na
Atomic #: 11
Atomic Mass: 23
Determine…
Protons ( + ) = 11
Neutrons ( 0 ) =12
Electrons ( - ) = 11
Valence Electrons? = 1
P:11
Na N:12
Draw an atom of…
Beryllium: Be
Atomic #: 4
Atomic Mass: 9
Determine…
Protons ( + ) = 4
Neutrons ( 0 ) = 5
Electrons ( - ) = 4
Valence Electrons? = 2
P:4
Be N:5
Draw an atom of…
Neon: Ne
Atomic #: 10
Atomic Mass: 20
Determine…
P:10
Protons ( + ) = 10
Ne N:10
Neutrons ( 0 ) =10
Electrons ( - ) = 10
Valence Electrons? = 8
NEON IS A STABLE ELEMENT (OR UNREACTIVE)
BECAUSE IT’S OUTER ENERGY LEVEL IS FULL!!!
Bell Ringer:
• Please pull out your Periodic Table
• Lets looks at the element: Chlorine
1. What is it’s Element Symbol?
2. What is it’s Atomic #?
3. How many Protons?
4. How many Neutrons?
5. How many Electrons?
6. Draw a Bohr model of Chlorine
7. How many electrons are in the valence shell?
8. Is the element stable or unstable?
Chlorine
1.
2.
3.
4.
5.
6.
7.
8.
What is it’s Element Symbol? Cl
What is it’s Atomic #? 17
How many Protons? 17
How many Neutrons? 18
How many Electrons? 17
Draw a Bohr model of Chlorine
How many electrons are in the valence shell? 7
Is the element stable or unstable? Stable
Cl P:17
N:18
Joke of the Day:
Chemical Compounds
• Compound: A combination of two or more
elements.
• Molecule: the smallest unit of a compound.
– Written as a chemical formula.
• Water is written as H2O because it contains two
atoms of Hydrogen and one atom of Oxygen.
• Table Salt is written as NaCl because it has one
atom of Sodium and one atom of Chlorine.
Let’s take a look at Chemical
Formulas
H 2O
Subscript: Tells you how many of each
atom are in the molecule. If there is no
subscript, there is one of that atom.
2H2O
Coefficient: Tells you how many of
each molecule you have. If there is no
number in front then there is one of
that molecule
Count the Atoms!




H = H:1
H2 = H:2
H2O = H:2 O:1
2H2O = H:4 O:2
***Molecules in parentheses are called Polyatomic Ions and always occur
together when they bond.
 H2(SO4) = H:2 S:1 O:4
 C7H5(NO2)3 = C:7 H:5
N:3 O:6
Chemical Bonds
• Ionic Bonds: Occurs when one or more
electrons are transferred from one atom to
another.
Ion: an atom with a positive or negative charge.
Ionic Bond = Giver + Taker
Givers won’t bond with Givers
Ionic Bonds
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Chemical Bonds
• Covalent Bond: Occurs when two atoms
share electrons
Covalent Bond = Taker + Taker
Givers won’t bond with Givers
What is theSpringfield High School
Mascot on the Simpsons?
Isotopes
• Isotopes: Atoms of the same element that
differ in the number of neutrons that they
contain.
– Radioactive Isotopes: Isotopes are unstable
and break down at a constant rate over time.
Dangerous but has practical uses.
• Dating rock layers, cancer treatment, food
preservation.
Isotopes of Carbon
Nonradioactive carbon-12
Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
Radioactive carbon-14
6 electrons
6 protons
8 neutrons