bellringer 1.draw a model for the following elements: a. sodium b. chlorine 2. how many valence...
TRANSCRIPT
Bellringer1. Draw a model for the following elements:
A. SodiumB. Chlorine
2. How many valence electrons does sodium have?
3. If sodium lost its valence electrons, what would its charge be?
4. How many valence electrons does chlorine have?
5. If chlorine gained an electron, what would its charge be?
Sodium
P: 11N: 12
XX
X XX
X X
XXXX
Chlorine
P: 17N: 18
X
XX X
X
X X
XXXX
X
X X
XX
X
2. One3. +1
1 A. 1 B.
4. Seven5. -1
I. Bonding Atoms
A. Atoms bond because their valence electrons interact
1. Bonding occurs so that atoms will have stable outer energy levels
a. What is a stable outer energy level? How many electrons?
i. 1st Energy level: 2e-
ii. 2nd, 3rd, 4th, etc…Energy level: 8e-
Example: Hydrogen
Valence electrons: 1Energy levels: 1
X X
The valence electron in each hydrogen is shared, giving each atom
a stable outer energy level.
II. Ionic Bonds
A. Ionic Bonds – Formed between oppositely charged ions
1. Metals form positive ions
2. Nonmetals form negative ions
B. When one atom loses an electron, another atom gains that same electron
1. Salt is formed from positively charged sodium ions and negatively charged chlorine ions
Example:
Na - [Na]+
Cl + [ Cl ]-
Sodium Ion (positive)
Chloride Ion (negative)
C. The chemical formula, NaCl, tells the ratio of sodium to chloride ions
D. Characteristics of ionic compounds:
1. Conduct electricity when dissolved
2. Metallic bonds – the attraction between a nucleus of one atom and the electrons from another atom
i. Causes atoms to pack close to each other
III. Covalent Bonds
A. Covalent Bond – Molecules, made when electrons are shared between atoms
Example: ChlorineSeven Valence Electrons
XXXXX
X
XX X
X XXX
X XX X
XXXXX
X
XXX
X XX X
X XX X
Cl ClThe line indicates shared electrons
1. Elements can form double or triple bonds
O O N Na. The compounds above share electrons
equally, so they form nonpolar covalent bonds
2. Not all covalent bonds are nonpolar
a. Water is a polar covalent molecule
Groups of covalently bonded atoms that have either gained or lost electrons
A. Polyatomic Ions –
IV. Polyatomic Ions
NH4+ ammonium
PO33- phosphite
NO2- nitrite
NO3- nitrate
OH- hydroxide
Polyatomic Ion Examples:
B. A polyatomic ion that is bonded with another atom is often indicated with parentheses
(NH4)2SO4
1. But not always
NH4NO3
Ammonium sulfate
Ammonium nitrate
C. Polyatomic ions usually end in -ate or -ite
1. -ate indicates one additional oxygen atom than the polyatomic ion with -ite
ClO3- chlorate
ClO2- chlorite
____ 1. SO42- A. sulfite
B. sulfate
____ 4. AsO33-
_____ 3. AsO43- C. arsenate
D. arsenite
Quiz: Match the polyatomic ion with its name
____ 2. SO32-A
D
C
B