Question

1. choose the best answer. which element would be used for shorthand electron configuration for calcium? ne ar he kr 2. choose the best answer. how many electrons does calcium have? 20 4 40 2

Explanation:

1. For shorthand electron configuration, we use the nearest noble gas with fewer electrons than the element. Calcium (atomic number 20) has an electron configuration of $1s^22s^22p^63s^23p^64s^2$. Argon ([Ar]) has an electron configuration of $1s^22s^22p^63s^23p^6$, which matches the inner electrons of calcium.
2. A neutral atom has the same number of electrons as its atomic number. Calcium has an atomic number of 20, so it has 20 electrons.

Answer:

1. [Ar]
2. 20