Chemistry Help: Protons Not Equal to Electrons

Question

Isn't the number of protons and electrons supposed to be equal?

There's an incomplete table we're supposed to fill out with four different symbols, protons, neutrons, electrons, and net charge. The problem is, on the last atom/molecule (whose symbol I don't know), there's 80 protons, 120 neutrons, and 78 electrons.

Any idea why the protons and electrons don't match up? Or what the symbol and charge must be?

Answer 1

The substance is Mercury (Hg) with an Atomic Number of 80 (Protons).

The Neutral atom contains 80 Electrons.

Your describing an 'Ionised Atom' of Hg(2+) as it has lost 2 electrons and therefore has 2 more Protons than Electrons.

Part 2:. It's zero charge and nothing is added.

As in Sodium Ion Na(+) + Chlorine Ion Cl(-) = NaCl. which is neutral. (no charge).

Answer 2

You can always figure out which element is being referred to when you know the number of protons. For 80 protons, the element would be mercury (Hg), #80 on the periodic table (atomic number =  number of protons).

The number of neutrons determines which isotope of mercury you are dealing with. In this case 80+120 = 200, so we are dealing with Hg-200 (see the link below for other naturally occurring isotopes of mercury).

When the number of protons and electrons don't equal one another, that means that the atom has a net charge (a.k.a. it is an ion). In the case above, that means the net charge would be +2 (2 more protons than electrons).

So you are dealing with 200-Hg^+2 (see the website below for how to write the isotope number, the +2 should be a superscript following the Hg symbol).

Answer 3

If the number of electrons does not match the protons than it is an ion. In this case it is a positive ion, also called a cation, because there are more neutrons than electrons. This ion has a charge of 2+.

If there are more electrons than protons than you have a negative ion which is called an anion.

When protons equal electrons the net charge is just 0.

Also for future reference, if the number of neutrons does not match the number of neutrons on the periodic table, then you have an isotope.  

Answer 4

The element is Mercury, symbol Hg. If it has 2 less electrons than protons then it has two extra positive charges, ie Hg++ or Hg2+. This is an ion implying the mercury is dissolved.