Science 9 unitB 3.1-3.3

Properties of ionic compounds

• metal + non-metal

• Metals are the positive ion

• Always solid at room temp

• Conduct electricity when dissolved in water

• Form crystals

• High boiling and melting point

• Charges balence out overall charge is zero

• Gives or gains electrons. Ion charges tell if its multivalent(more then 1 possible charge)

Properties of molecular compounds

• non-metal + non-metal

• Covalent bond

• Solid, liquid or gas at room temp

• Low boiling and melting point

• Poor conductors

Compound

Formed when we combine elements together. ex: water H2O

Element

Basic building block. Cannot be broken down into anything simpler. A single ingredient

Subscript

• Sub = below

• Subscript number tells us the amount for each element that follows.

IUPAC

International Union of Pure and Applied Chemistry

• where the rules of scientific names come from.

Ionic

Formed when a metal element combines with non-metal element

Molecular

(AKA covalent) formed when 2 non-metal elements combine

Ion charge

• ion charge = ionic compounds

• Tells you what the charge of that element would be if it becomes a ion

Atoms

• The element at its starting point, before it gives or gain any electrons.

• Doesn’t have a charge

Ions

• the element after it’s given or gained electrons while forming a compound

• Has a charge

• Cations are positive, lost electrons. (CAT in cations think lucky cat = positive)

• Anions are negative, gained electrons. (Anions sounds like onions = cry which is bad like negative)

Multivalent ions

Have more then one options for the charge, the name tells us what the charge is. Told in Roman numerals

Polyatomic ions

• “Poly” = many.

• Polyatomic ions are groups of elements acting together as on ion with one charge.

• One element even if it looks like 2. Ex: carbonate CO3

• Don’t change ending to “ide”

Ionic compound names

1. Write metal name

2. Write non-metal name

3. Change ending to “ide”

Ionic compound formula

• cross trick

1. Write symbol and the charge for each element

2. Balance the charges(find lowest common number)

3. Write each element with its matching subscript number

Covalent compound names

1. Write the name of the element in the order they appear

2. Change end of the last element to “ide”

3. Indicate how many of each element you need in the name

Prefixes

1. Mono

2. Do

3. Tri

4. Tetra

5. Penta

6. Hexa

7. Hepta

8. Octa

9. Nona

10. Deca

Covalent compound formulas

1. Find the element for the given symbol

2. The prefix number becomes the subscript number.

3. No states needed in grade 9 for molecular compounds

Diatomic atoms

• special molecular compound

• Consists of two atoms. Ex: hydrogen (H2), oxygen (O2), and the halogens: fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), and astatine (At2).

Homonuclear

Consist of the same element

Heteronuclear

Two different elements Ex: HBr, CO