Why was the concern over global cooling replaced with a concern over global warming? a. the science community needed a cause to frighten the general population. b. steady surface temperature increases were noted between the 1970’s and 90’s. c. air pollution only became a concern in the 1980’s. d. scientists observed severe ocean acidification.

b. Steady surface temperature increases were noted between the 1970’s and 90’s.

Explanation:

It was the notable observation of steady rise in surface temperature on earth around the 1970’s that brought the issue of climate change into limelight.

One of the effect of climate change is that it causes global warming. Global warming is attributed to greenhouse gases which traps heat on the earth surface and causes the surface to warm. This can lead to melting of polar ice and an increase in water volume in oceans.

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.