which statements are correct about halides

whwn we go down the group:

which one is radioactive

it is correct ?

group A1 is called alkali metals

when we go down the group(alkali metals):

-atoms get ..................

when we go down the group(halogens) atoöms get larger so .......................................... between the incoming electron and the nucleus decreases.

whe atoms get bigger it becomes more ................................................. to gain electron.