floats on water and reacts violently
burns with a lilac flame

potassium
K

atoms of this element form four covalent bonds

carbon
C

non-metal diatomic (in pairs) - 78% of atmosphere
forms 3 covalent bonds
unreactive, used for light bulbs and packaging food

nitrogen
N? molecules

unreactive yellow metal
found �native�or uncombined in the Earth�s crust

gold
Au

metal which forms 3+ ion
low density

aluminium
Al

non-metal
forms oxides which cause acid rain

sulfur
S

non-metal diatomic (in pairs)
red-brown LIQUID at room temperature

bromine
Br? molecules

only metal which is liquid at room temperature

mercury
Hg

non-metal diatomic gas (in pairs)
test for this is a squeaky pop with burning splint

hydrogen
H? molecules

pale yellow diatomic GAS (in pairs)
most reactive element in group 7

fluorine
F? molecules

obtained from its ore by reduction with carbon
reacts with water and oxygen to form iron oxide (rust). Can form �? AND �? ions (II) and (III)

iron
Fe

metalloid used as a semiconductor in electronics
- has some properties of metals and non-metals

silicon
Si

orange/red metal used for wires, pipes & coins
good conductor of heat and electricity
unreactive, forms �? ion

copper
Cu

radioactive metal which is the heaviest naturally-occurring element
used in nuclear fission power stations

uranium
U

silvery metal
used in the manufacture of stainless steel alloys

chromium
Cr

metal which burns in air with a bright white flame
gains two electrons to form a �? ion

magnesium
Mg

diatomic gas (in pairs) is 21% of atmosphere
test is that it relights a glowing splint

oxygen
O? molecules

grey diatomic solid (in pairs)
forms purple gas when it sublimes

iodine
I? molecules

metal with very high melting point, used in old-style incandescent light bulbs

tungsten
W

metal that fizzes and floats on water
red flame when reacts with air

lithium
Li

metal that melts into a ball, fizzes and floats when it reacts with water
orange flame when it burns in air

sodium
Na

pale yellow green diatomic gas (in pairs)
used to disinfect water e.g swimming pools by killing bacteria

chlorine
Cl? molecules

heavy metal that forms a 2+ ion
forms insoluble white precipitate with chloride and sulfate ions

lead
Pb

group 2 metal with an insoluble white sulfate

barium
Ba

most reactive element in group 1
loses its outer electron very easily

caesium
Cs

metal used in alloys with copper (to make brass)
forms �? ion

zinc
Zn

unreactive metal that forms insoluble precipitates with group 7 ions

silver
Ag

unreactive gas that makes up 1% of the atmosphere
has full outer shell of electrons

argon
Ar