1. How Atoms Combine (7.3)

2. Atoms combine to become more ________.
The most stable elements in the periodic table are the ___________________ because they have the maximum number of _____________ in their outermost orbits. (they have _____ valence electrons)
Elements ________ to try and get a valence shell.
There are 3 ways in which an atom that does not have a full valence shell can fill it:
1. it can __________ electrons,
2. it can __________ electrons,
3. it can __________ electrons.
All 3 methods result in the formation of a chemical ___________. A chemical bond is the attraction between 2 _________.
stable
Noble gases
electrons 8
react
full
gain
Ionic bond
lose
share
covalent bond
bond
atoms

3. IONIC COMPOUNDS (metals & non-metals)

4. IONIC BONDING metal non-metal oppositely charged
Ionic bonds are formed between __________ elements and _____________ elements. Circle the compounds below that contain ionic bonds. KCl H2O O2 MgO Na2S NH3 Cl2 Ionic bonds are formed by the attraction of 2 ____________ charged ions (an ion is a _________ particle).
metal
non-metal
oppositely
charged

5. IONIC COMPOUNDS + - Na Cl Example 1: Sodium (Na) and Chlorine (Cl) 1117

6. IONIC BONDING
Example 1: Sodium (Na) and Chlorine (Cl)
the sodium atom its outermost electron to chlorine so that both atoms get a full outer shell (and become ___________). Sodium has lost an electron and now has a _____________ charge, while chlorine has gained an electron and now has a _____________charge.
______________ charged atoms ___________, forming an _____________ bond.
loses
stable
positive
negative
oppositely
attract
ionic

7. IONIC BONDING - + + - F Mg F
Example 2: Magnesium (Mg) and Fluorine (F) - F 9 + + Mg 12 - F 9

8. IONIC BONDING
Example 2: Magnesium (Mg) and Fluorine (F)
Magnesium needs to lose electrons. Fluorine needs to gain electron. Magnesium can only lose two electrons if it reacts with fluorine atoms.
The formula for this compound is ___________ 2 1 2
MgF2

10. Molecules & Covalent Bonding

11. Molecules & Covalent Bonding
Covalent bonds are formed from ____________ elements.
Unlike ionic bonds that are formed from ions that have ______ or ________ electrons, covalent bonds are formed from atoms that _______ electrons.
The attraction of 2 atoms for the shared pair of electrons results in a __________ bond.
Two or more atoms joined by covalent bonds form a __________.
non-metal
lost
gained
share
covalent
molecule

12. Molecules & Covalent Bonding
Example #1: Hydrogen Molecule
The hydrogen molecule consists of 2 hydrogen atoms. Each hydrogen atom has _____ valence electron. If each atom shares its electron with the other atom, then each atom has _____ electrons in their outer shell (1st shell). The shell is now full and the atoms (and molecule) are ______________. 1 2
stable

13. Molecules & Covalent Bonding
Bohr-Rutherford diagrams:
Electron Dot diagrams:
H H H H H2
The formula for a hydrogen molecule is

14. Molecules & Covalent Bonding
Example #2: Hydrogen and Chlorine
Hydrogen and chlorine each need more electron in order to have a full shell. They do this by one pair of
Electron Dot diagrams:
H Cl H Cl
The formula for the compound with hydrogen and chlorine is 1
sharing
electrons
HCl

15. Molecules & Covalent Bonding
Example #3: Hydrogen and Oxygen
Hydrogen needs more electron in order to have a full outer shell. Oxygen needs ____ more electrons to have a full outer shell. Oxygen can get a full shell if it shares its 2 unpaired electrons with hydrogen atoms. This also gives each hydrogen atom a full outer shell. 1 2 2

16. Molecules & Covalent Bonding
Electron Dot diagrams:
H O O H
H H
The formula for the compound with hydrogen and oxygen is This compound is known as ________.
H2O
water

17. Molecules & Covalent Bonding
NOTE: When drawing electron dot diagrams for a molecule, use the stable octet rule. With the exception of hydrogen, each atom of the molecule should have 8 electrons (dots) surrounding it (including shared electrons).

18. dissolved in water - yes
Ionic
Compounds
Molecular (Covalent)
Type of Bonds
ionic
covalent
Types of Elements involved
metals & non-metals
non-metals only
State at 20C
solid
solids, liquids, gases
Forces between Ions or Molecules
very strong
weak
Melting & Boiling Points
high
relatively low
Solubility in Water
soluble
many are not soluble
Conducts Electricity?
solid – no
liquids – yes
dissolved in water - yes no
Examples
NaCl (salt)
CaO
AgNO3 H2
H2O
CCl4