atomic structure

periodic table

properties of elements

The atom

electronic structure

groups

periods

group 1

group 7

image

Protons: mass =1, charge of + 1 in the nucleus

neutrons: mass = 1, the charge is neutral, found in the nucleus

electron: charge is negative, -1, mass is negligible, orbit in the shells

electrons are in shells

up to 2 electrons in the first shell

up to 8 electrons in the rest of the shells (GCSE)

atomic number

it's the number of protons, which is also the same amount of electrons in an atom

neon is 10

relative atomic mass number

it is the number of particles in the atom

neon is 20

image

1 electron in the outer shell, so it's very reactive, reactivity increases down the group, (go down, more reaction)

7 electrons in the outer shell, react by gaining electron, reactivity decreases down the group, ( go down, less reaction)

group 0

outer shells are full, chemically aren't reactive, stable (boring)

period number tells you the number of shells the element has

eg. Nitrogen is in period 2, has 2 shells of electrons

metals

non metals

properties: they are are thermal and electrical conductors, malleable (flexible), and ductile (can be pulled into a wire), generally quite dense, and solid at room temperature, high melting and boiling points

properties: thermal and electrical insulators, brittle (they can snap), can be solid, liquid, or gas, with low melting and boiling points, generally less dense than metals