Covalent and Ionic Compounds

SNC1D

Different ways for atoms to combine…• Metal + Non-Metal

– form compound made up of charged particles that become ions by gaining or losing electrons

• Non-Metal + Non-Metal

– Electrons are shared between atoms

• Metal + Metal– Alloys created by melting two or more metals and

then mixing them

Molecular Compounds

• Two non-metals combine to form a covalent bond whereby electrons are shared between atoms

• By sharing electrons, each atom will have a stable octet

• What is the difference between an ionic bond and a covalent bond?

- An ionic bond is a chemical bond whereby one atom loses electrons to become a positive ion and another gains electrons to become a negative ion- A covalent bond involves the sharing of electrons between atoms in a molecule

Examples of molecular compounds:

• Carbon monoxide• Carbon dioxide• Nitrogen trifluoride• Sulfur hexafluoride

Naming molecular compounds: # of atoms prefix

1 mono-

2 di-

3 tri-

4 tetra-

5 penta-

6 hexa-

7 hepta-

8 octa-

9 nona-

10 deca-

-Add the appropriate prefix depending on the number of each of the atoms in the compound

-If there is only one of the first element in the formula, the mono- prefix is dropped

Write the names for the following molecular compounds:

CCl4

PCl3

NBr3

H2S

H3P

Molecular Elements• Atoms that exist in pairs in nature

• Referred to as diatomic molecules and there are seven

H2, N2, O2, F2, Cl2, Br2, I2

Counting elements in molecules…

NaHCO3 (baking soda)

How many elements does this compound contain?

How many atoms of each element are in baking soda?

What about CH3COOH? (vinegar)

Different ways for atoms to combine…• Metal + Non-Metal

– form compound made up of charged particles that become ions by gaining or losing electrons

• Non-Metal + Non-Metal– Nucleus of one atom forms strong attraction to valence electron

of another atom– “tug of war” for electrons occurs, but neither atom wins – Instead, the two atoms share each other’s electrons, resulting in

a what we call a covalent bond that holds the atoms together • Metal + Metal

– Alloys created by melting two or more metals and then mixing the

– Different from compounds because they are solutions of metals and atoms are not chemically joined

IONIC COMPOUNDS(metal + non-metal)

• Ionic compound: a compound that consists of positively and negatively charged ions

• Atoms want to be stable• In ionic compounds, atoms become stable by either

gaining or losing electrons to accomplish a full outer shell

• An ionic bond is created

Important terms…

• Ion: a particle that has either a positive or a negative charge

• Cation: a positively charged ion

• Anion: a negatively charged ion

• What would have to happen to a lithium atom in order for it to become chemically “stable”?

• What could it join with in order to accomplish this?

Bonding Between Alkali Metals and Halogens

FLUORINE CHLORINE BROMINE IODINE

LITHIUM LiF LiCl LiBr LiI

SODIUM NaF NaCl NaBr NaI

POTASSIUM

KF KCl KBr KI

Naming:-The name of the metal does not change-the name of the non-metal takes an “ide” ending

Ex. NaCl Sodium chloride

Mg

vvvv

vvvv

Cl

Cl2+

1-

Ca ClNeeds to lose 2 electrons

Needs to gain 1 electron

CaCl2

Bonding between Alkaline Earth Metals and Halogens

FLUORINE CHLORINE BROMINE IODINEBeryllium

MagnesiumCalcium

BeF2 BeCl2 BeBr2 BeI2

MgF2 MgCl2 MgBr2 MgI2

CaF2 CaCl2 CaBr2 CaI2