Chem 9 - Unit 2 (Elements and the periodic table)

Atomic Number

Number of protons in an atom

Atomic Mass (AMU)

sum of protons and neutrons

Ion Charge

The charge atoms like to have

Metal properties

shiny, malleable, ductile, conductive, usually solid, quite dense, alkali metals —> very reactive

Non-metal properties

dull, usually solid/gas, usually less dense, halogens are very reactive

Metalloid

exhibit some qualities of both metals and non metals (e.g silicon)

Period

Row

Group/families

Columns, have similar properties

Where/what are alkali metals

very left column of the periodic table, highly reactive, low melting point, good conductors, silver/grey

Where/what are alkaline earth metals

second column, silvery white, higher melting point than alkali metals, good conductors, very reactive

Where/what are halogens

Group 17, range of bright colours as gases, very toxic, reactive with hydrogen to form acids

Where/what are noble gases

Group 18, colourless, gas at room temperature, not reactive

Hydrogen

colourless, gas at room temp, very reactive, burns in air

Going across the periodic table

each row is a period, as you go across the protons increases

Going down the periodic table

each column is a chemical family/group, similar properties

Atomic Radius

radius of the atoms decrease as you go from left to right (number off protons increases to attract electrons)

radius gets bigger as you go down as there are more electrons