Unit 1.1 Fundimental Ideas

Atoms consist of a nucleus surrounded by electrons. Each element is made of one type of atom. 

 Atoms are represented by chemical symbols e.g. calcium is Ca.

Elements in the periodic table are arranged in columns, called groups-the elements in a group usually have similar properties. Main Groups Are:

·         Alkali Metals   Alkaline Earth Metals

·         Transition Metals  Other Metals

·         Metalloids Other Non-Metals

·         Halogens  The Noble Gases

COMPOUNDS contain more than one element combined together.

Elements are arranged in order of atomic number in the periodic table.

The atomic number (proton number) is equal to the number of protons in the nucleus of the atom.

The nucleus is made of protons and neutrons this combined equal the mass number.

Electron - negative (-1) charge, orbits the nucleus in shells, little mass

Proton - positive (1) charge.

Neutron - no charge (0).

All elements in the same group of the periodic table have the same number of electrons in their highest energy level (outer shell). There are 2 atoms in the first shell then up to 8 in the consecutive shells.

Diagram on next card -------->

Ionic Bonding

When a non-metal reacts with a metal, ions are formed. Metal atoms lose one or more electrons to form positively charged ions. Non-metals gain electrons, forming negatively charged ions.

 Ionic bonds are formed when the oppositely charged ions attract.

Ionic compounds conduct electricity when dissolved in solution or molten and have high melting points; also they tend to dissolve in water.

The chemical formula tells us the simplest ratio of ions in the compound.

 Covalent Bonding

Covalent bonding is bonding between two non-metals,  this is where they share their electrons and molecules are formed.

The chemical formula tells us the number of atoms that have bonded together.

In a chemical equation atoms re-arrange themselves to form new substances (products). 

ATOMS ARE NEITHER CREATED NOR DESTROYED IN A CHEMICAL REACTION! 

This means the mass of the products is the same as the mass of the reactants.