Witch one is a gas metal or ionsodium, potassium, hydrogen, lithium

Lithium, sodium and potassium are in the same group, alkali metals or Group 1A, because the Periodic Table is arranged according to the Periodic Law which states that chemical properties repeat at regular intervals.

Explanation: hope it helps :)

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→

b.

the accuracy of the data.