An ion y3+ has 18 electrons and 24 neutrons. determine the proton number and nucleon numbe. r of the element y

A neutral atom has the same number of protons and electrons. Anytime an element  has a charge, that means either more electrons or protons were added.
more electrons= negative charge
more protons = positive charge
Your charge is +3 which means there are 3 more protons than electrons
First answer is proton number is 21
The nucleon number means mass number which is protons + neutrons
24 + 21 = 45
Nucleon number is 45

Are there any options?