OCR A Chemistry 2.1.1/2.1.2/2.2.1 Atomic/electron structure and isotopes, compounds formulae

Proton relative mass

1

Neutron relative mass

1

Electron relative mass

1/1800

Define isotopes

Atoms of the same element with the same number of protons, different number of neutrons

Define relative isotopic mass

Mass of one isotope compared to 1/12th the mass of one atom of carbon-12

Define relative atomic mass

Weighted mean mass of one atom compared to 1/12th the mass of one atom of carbon-12.

Define relative atomic mass

Average mass of a molecule compared with 1/12th the mass of carbon-12.

Ammonium ion

NH4 +

Silver ion

Ag +

Zinc ion

Zn 2+

Nitrate ion

NO 3 -

Carbonate ion

CO3 2-

Sulphate ion

SO4 2-

Hydroxide ion

OH -

Define atomic orbital

Region around a nucleus which can hold upto 2 electrons with opposite spins.

shape of an s orbital

Spherical

Shape of p orbital

dumbbell shaped