In chemistry and atomic physics, the main group is the group of elements whose lightest members are represented by helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, and fluorine as arranged in the periodic table of the elements
22) Oxygen with a -2 charge
23) Neon with a +2 charge
24) Fluorine with a -1 charge
25) Lithium with a +1 charge
Answer:

Explanation:
Hello!
In this case, given the masses of copper, zinc and lead, it is possible to compute the moles via their atomic masses first:

Now, we compute the atomic percentages as shown below:

Best regards!
12 protons
13 neutrons
12 electrons
An isotope is an atom with a different number of neutrons but same number of protons