group 7 elements Flashcards
fluorine
very reactive, poisonous yellow gas
chlorine
fairly reactive, poisonous, dense green gas
bromine
dense, poisonous, red-brown volatile liquid
iodine
dark grey crystalline solid or a purple vapour
what do all halogens exist as?
molecules (pairs of atoms)
what is the trend in reactivity going down the group?
it decreases
why does the reactivity decrease as you go down the group?
it’s harder to gain an extra electron as the outer shell is further from the nucleus
what is the trend in melting and boiling points going down the group?
they increase
what is the trend in atomic mass going down the group?
it increases
how many electrons are on the outer shell?
7
what compounds do halogens form?
covalent and ionic
what ion do halogens form?
1-
when will a displacement reaction occur?
between a more reactive halogen and the salt of a less reactive one
