Bonding Basics

Bell Work 11/15

6CF₄1. How many Carbon atoms are in the above

molecule.2. How many Flourine atoms are in the above

molecule?

C₆H₁₂O₆3. How many Carbon atoms are in the above

molecule.4. How many Hydrogen atoms are in the above

molecule?

• An atom that gains one or more electrons will have a negative charge.

• An atom that loses one or more electrons will have a positive charge.

Ions• An atom that gains or loses one or more

electrons is called an ion.

2 Types of Bonds

• Ionic Bond• Covalent Bond

Ionic Bond• A chemical bond in which one atom loses an

electron to form a positive ion and the other atom gains an electron to form a negative ion.

In this example, will sodium have a positive or negative charge?

2 Types of Ions

• A positive ion is called a cation• A negative ion is called an anion

Polyatomic Ions• Polyatomic ions: ions that are made of more

than one atom– Ex. An ammonium ion is made of nitrogen and

hydrogen atoms.

Covalent Bond• Atoms share one or more electrons with each

other to form the bond.

– Each atom is left with a complete outer shell.

Covalent Bond

• Double bond: two atoms share two pairs of electrons

Covalent Bond

• Triple bond: atoms share three pairs of electrons

Covalent Bond

• Atoms of some elements pull more strongly on shared electrons than do atoms of other elements. As a result, the electrons are pulled more toward one atom, causing the bonded atoms to have slight electrical charges.

– Polar bond: a covalent bond in which electrons are shared unequally

– Nonpolar bond: a covalent bond in which electrons are shared equally

Covalent Bond

• Covalent bonds usually form between atoms of nonmetals.

• In contrast, ionic bonds usually form when a metal combines with a nonmetal.

Covalent Bond

Chemical Formulas• Subscript: tells you the ration of elements in

the compound.– Ex. MgCl₂

• This means that for every magnesium ion there are two chloride ions.

– Ex. CaCO₃• This means one calcium, one carbon, and three oxygen

ions.

• If no subscript is written, the number 1 is understood.– Ex. NaCl

• This means there is one chloride ion for every sodium ion (1 to 1 ratio).

Chemical Formulas

– Superscripts are the big number in front of an atom or molecule. They tell you how many atoms there are of that element.

• Ex. 4H– This means four atoms of hydrogen.

Chemical Formulas

– When a superscript is in front of a molecule, it multiplies the whole molecule.

• 3H₂O– Here there are 6 hydrogens and 3 oxygens

– Basically like this: HHO HHO

HHO

Chemical Formulas

Naming Covalent Bonds1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 heptaa

8 octa

9 nona

10 deca

* Second element in ‘ide’ from

* Drop –a & -o before ‘oxide’

N2S4 dinitrogen tetrasulfide

XeF6 xenon hexafluoride

P2O5 diphosphorus pentoxide

SO3 sulfur trioxide