Answer:
d.have a mass of 1 amu..
Explanation:
Does not match a as the answer for a is electrons B.electron circle around the nucleus because neutrons are inside the nucleus.C.proton and neutrons make the nucleus so the only answer left is .d .which is correct
Answer: because they take a lot of tie to form
100% find the gfm of both sides then divide
Answer:
Electrons arrangement change is almost constant down the group, hence nuclear charge is almost constant.
But the energy levels on which electrons are arranged increase down the group, hence shielding or screening effect increases.
They're both a part of an atom.