<span>Ionization energy (IE) is the amount of energy required to remove an electron.
If you observe the IEs sequentially, there is a large gap between the 2nd and 3rd. This suggests it is difficult to remove more than 2 two electrons. Elements that lose two electrons to become more stable are found in the Group 2A (2 representing the number of electrons in the outermost valence shell).</span>
Answer:
D. Protons ; neutrons.
Explanation:
For a given element the number of protons is fixed, but the number of neutrons differ because the element usually consist of a number of isotopes.
For example Carbon has isotopes which contain 12, 13 and 14 neutrons.
So that is why you average the number of neutrons to find the approximate atomic mass..
Circumpolar constellations stay in the sky. Because of the rotation of the Earth and its orbit around the Sun, we divide the stars and constellations into two groups. Some stars & constellations never rise nor set, and they are called circumpolar.
