Chemistry For Dummies Direct

: Neutral particles in the nucleus; they add mass but don't change the element's identity. Variations in neutron counts create isotopes .

: These indicate the number of electron shells an atom has. Chemistry For Dummies

At the heart of chemistry is the , the smallest unit of an element that retains its properties. : Neutral particles in the nucleus; they add

: A "partnership" where two non-metals share electrons to fill their outer shells. Whole of AQA GCSE Chemistry paper 1 in 1hr 15 mins : Neutral particles in the nucleus

: Positively charged particles in the nucleus; the number of protons defines what element an atom is (its atomic number).