| Define electronegativity | The tendency for an atom of a given chemical element to attract shared electrons when forming a chemical bond |
| Define ionisation energy | The amount of energy required to remove an electron from an isolated atom or molecule. |
| Define valency | The ability of an atom to form chemical bonds with other atoms |
| What is the trend of ionisation energy? | Ionization energy increases moving from left to right across an element period (This is due to valence shell stability).
Ionization energy of the elements within a group generally decreases from top to bottom (This is due to electron shielding). |
| What is the trend of electronegativity | Electronegativity decreases down a group and increases across a period |
| What is the trend of valency? | Valency first increases and then decreases as we go from left to right in a period but remains the same in a group. |
| Define a metallic element | Any chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc |
| Define non-metallic elements | A chemical element (such as boron, carbon, or nitrogen) that lacks the characteristics of a metal. |
| Define an alkali metal | Very reactive chemical species that readily lose their one valence electron to form ionic compounds with nonmetal elements |
| Define a halogen | They are reactive non-metallic elements that form strongly acidic compounds with hydrogen. |
