Structure, periods and groups

What does the number of protons determine?

atomic number

What are periods and groups?

• Periods: horizontal rows

• Groups: vertical rows

Properties of metallic elements:

• lustrous

• conduction of heat and electricity

• malleable

• ductile

• hard

• high melting point

Explain alkaline earth metals and its properties

• 2 electrons in the valence shell

• low melting point

• soft and very reactive (not quite as reactive as group 1)

• reaction with water is the same as alkali metals

Explain transitional metals and its properties

1. a small number are magnetic

2. gold and copper are the only metals that aren’t silvery in colour

3. many forms coloured compounds

4. many forms more than one compound with a non-metal.

Explain metalloids and its properties

• they are the small set of elements along the ‘staircase’ diagonal boundary between the metal and non-metals

• they are there since they have a mixture of properties between those of metals and non-metals

• They conduct electricity. Three of them are semiconductors, meaning they only conduct electricity under certain conditions

Explain non-metals and its properties not lustrous or ductile

• not lustrous or ductile

• some are brittle

• much larger range of melting point and boiling point than metals

• at room temperature, several non-metals are gases and one of them, which is bromine, is a liquid

• only 16 elements are considered non-metals

• they make up most of the crust and atmosphere of the earth, as well as the bulk of living organisms’ tissues

Explain halogens and its properties

• 7 electrons in valence shell

• react with metals to form salt

• some have bleaching properties

• boiling and melting points increase as you go down the group

• at room temperature, fluorine and chlorine are gases, bromine is a liquid and iodine, and astatine are solids. Astatine is radioactive and very unstable, and fluorine is the most reactive non-metal and extremely dangerous

• the further you go down, the less reactive it is

• very effective in cleaning and sterilisingEx substances

Explain noble gases and its properties

• 8 electrons in the valence shell

• all gases at room temperature and remain unchanged if mixed with other elements

• very unreactive

• the first three don’t react with other elements and form no compound

• the last one which is radon is a radioactive gas and very dangerous