The atomic number of magnesium is 12. How many protons are there in the nucleus of the magnesium atom? How many electrons and protons does an ion of magnesium which has a charge of +2 contain?

(A) 10, 10

(B) 10, 13

(C) 11, 12

(D) 10, 12

The atomic number of an element is a fundamental property that tells us a lot about that element. For magnesium, which has an atomic number of 12, this means that there are 12 protons in the nucleus of a magnesium atom. Protons are positively charged particles, and they play a crucial role in defining the identity of an element. Since magnesium is neutral in its elemental form, it also has 12 electrons, which are negatively charged particles that balance the positive charge of the protons.

Understanding Magnesium Ions

When magnesium forms an ion, particularly a magnesium ion with a charge of +2, it means that it has lost two electrons. This loss of electrons results in a net positive charge because the number of protons (which remains unchanged) exceeds the number of electrons.

Calculating the Number of Electrons in the Ion

To determine the number of electrons in a magnesium ion with a +2 charge, we start with the neutral magnesium atom:

• Protons: 12
• Electrons: 12 (in a neutral atom)

When two electrons are lost to form the +2 ion:

• Electrons in the ion: 12 - 2 = 10

Summary of the Ion's Composition

So, for a magnesium ion with a +2 charge, we have:

• Protons: 12
• Electrons: 10

Now, looking at the options provided:

• (A) 10, 10
• (B) 10, 13
• (C) 11, 12
• (D) 10, 12

The correct answer is not explicitly listed in the options as pairs of protons and electrons. However, we can conclude that the magnesium ion with a +2 charge contains 12 protons and 10 electrons. Therefore, the answer aligns with the understanding that the ion has 12 protons and 10 electrons, which is not directly represented in the options but can be inferred from the context.