Question

which statement describes the relationship between two electrons in an atom of magnesium in the ground state?
1 an electron in the first shell has the same amount of energy as an electron in the second shell.
2 an electron in the first shell has a greater amount of energy than an electron in the second shell.
3 an electron in the second shell has the same amount of energy as an electron in the third shell.
4 an electron in the third shell has a greater amount of energy than an electron in the second shell.

Explanation:

Electron shells (energy levels) in an atom have increasing energy as their shell number (n) increases. For ground-state magnesium, electrons in higher-numbered shells are farther from the nucleus and have greater energy.

• Option 1 is wrong: Shell 1 has lower energy than shell 2.
• Option 2 is wrong: Shell 1 has less energy than shell 2.
• Option 3 is wrong: Shell 2 has lower energy than shell 3.
• Option 4 is correct: Higher shells have greater energy.

Answer:

1. An electron in the third shell has a greater amount of energy than an electron in the second shell.