chem atomic structure gcse

isotope def.

diff forms of same element containing same num of protons but diff num of nuetrons

atoms of same element w diff num of nuetrons but same num of protons and electrons

mass number

num protons + num nuetrons

atomic number

num of protons and electrons

how to find num of nuetrons

mass num - atomic num

why r electronic arrangements important?

tell u how atom will react chemically

relative atomic mass

weighted av mass of isotopes of element compared to 1/12 mass of carbon-12

sum for relative atomic mass

(mass of isotope x abundance) + (mass of isotope x abundance) / 100

why do isotopes have diff physical properties

diff masses

all hydorgens have

1 proton and 1 electron

def molecule

2 or more atoms chemically bonded

compound def

2 or more diff atoms chemically bonded