Chemistry Chapter 6

chemical bond

attraction between atoms or ions toform a new substance -- a compound

compound is a pure substance made up

2 or more elements chemically combined.

A neutral molecule is made of

two or more atoms held together by covalent bond.

Covalent bonds

atoms share one or more pairs of electrons to form molecules with no net electrical charge (unless a polyatomic ion)

Covalent bonds commonly form

between two non metals.

Ionic bonds

the attraction of ions of opposite electrical charge (Ion -- atom or group of atoms with a net charge)

At 25°C and 1 atm pressure some elements exist as diatomic molecules or other more stable forms

H2 N2 O2 F2 Cl2 Br2 I2 S8 P4 (red)

To name binary covalent inorganic compounds, name the first element with the normal element's ending followed by

the second one with an ide ending.

Also if two elements can form more than one compound, use the following prefixes to indicate the number of the atoms:

mono=1 di=2 tri=3 tetra=4 penta=5 hexa=6 For the first element sometimes mono is omitted.

oxidization

Cations have a plus charge and are formed by loosing electrons

Group 1A elements usually only form

+1 ions

Group 2A elements usually only form

+2 ions

To name simple cations just name the metal followed by the word

ion

For metal which form more than one cation

Roman numerals are used to indicate the charge.

Simple monatomic anions are named with an

ide ending.

Halogens (group 7A) form

-1 monatomic ions

Group 6 A form

-2 monatomic ions

Group 5 A form

-3 monatomic ions

In ionic substance a positive ion attracts a negative ion according to Coulomb Law = ?

Force of Attraction

Polyatomic ions

ions with 2 or more atoms covalently bond to each other (they have a net charge on them)