Which of the following is an example of kinetic energy?
A. a boy resting on a park bench
B. a book sitting on a shelf
C. a rubber band stretched as far as it can go
D. a swing moving back and forth

D

Explanation:

Kinetic energy means the energy of motion. Answer choices A, B, and C are all examples of things that are not moving or have potential energy, meaning that it could be converted to kinetic energy but is not right now. However, a swing moving back and forth is motion, meaning that it has kinetic energy. Hope this helps!

D) A swing moving back and forth

Explanation:

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.