Question

1. choose all that apply.

which two sublevels does calcium have?
s
f
d
p

1. choose the best answer.

which of these element groups is most reactive, especially in water?
alkaline earth
transition
alkali

Explanation:

• For question 17: The electron configuration of calcium (\(Ca\)) is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\). From this configuration, we can see that it has electrons in \(s\) and \(p\) sublevels.
• For question 18: Alkali metals (Group 1 elements) are extremely reactive, especially with water. They react vigorously to form hydroxides and hydrogen gas. For example, sodium (\(Na\)) reacts with water as \(2Na + 2H_{2}O=2NaOH + H_{2}\uparrow\). Alkaline - earth metals (Group 2) are less reactive than alkali metals with water, and transition metals (d - block elements) are generally less reactive with water compared to alkali metals.

Answer:

1. A. s, D. p
2. C. alkali