Everything on the GCSE Chemistry The Periodic Table poster is written out below, section by section. Use it to search the sheet, copy parts into your own notes, or check a fact quickly.
How the periodic table is organised
Elements are arranged in order of increasing atomic (proton) number. Each element is shown with its chemical symbol, atomic number and relative atomic mass.
Periods
Periods are the horizontal rows. Moving across a period, each element has one more proton and one more electron than the element before it. Each new period marks the start of filling a new electron shell.
Groups
Groups are the vertical columns. Elements in the same group have the same number of electrons in their outer shell, which gives them similar chemical properties.
Metals and non-metals
A staircase line on the table divides metals (to the left and bottom) from non-metals (to the right and top).
| Metals | Non-metals | |
|---|---|---|
| Position | Left and bottom of the table | Right and top of the table |
| Ions formed | Lose electrons to form positive ions | Gain electrons to form negative ions, or share electrons in covalent bonds |
| Conductivity | Conduct heat and electricity | Mostly do not conduct |
| Appearance | Shiny, malleable and ductile | Often dull and brittle |
| At room temperature | Mostly solid (mercury is a liquid) | Mix of solids, liquids and gases |
Group 1: the alkali metals
Group 1 elements have one electron in their outer shell. They are soft metals that react vigorously with water to form alkaline solutions – hence the name alkali metals.
Trends going down the group
- Reactivity increases – the outer electron is further from the nucleus and more shielded, so it is easier to lose.
- Melting and boiling points decrease – the metallic bonds weaken as the atoms get larger.
Group 7: the halogens
Group 7 elements have seven electrons in their outer shell. They exist as diatomic molecules: , , and .
Trends going down the group
- Reactivity decreases – the outer shell is further from the nucleus, so it is harder to gain an electron.
- Melting and boiling points increase – the molecules get larger and the intermolecular forces strengthen.
States at room temperature
Fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid.
Group 0: the noble gases
Group 0 elements are unreactive because they already have a stable outer-shell electron arrangement. All have eight outer-shell electrons except helium, which has two.
All noble gases are colourless gases at room temperature.
Trends going down the group
Boiling points increase with relative atomic mass, because the atoms get larger and the intermolecular forces between them strengthen.
Transition metals
Transition metals (in the central block of the table) form coloured compounds, act as useful catalysts, and can form ions with variable charges – for example and .
Compared with Group 1 metals, transition metals are harder, stronger, denser, have much higher melting points, and are much less reactive with oxygen, water and halogens.