Given the following information, calculate the mass for b-11. b-10 has a natural abundance of 19.9
percent, while b-11 has a natural abundance of 80.1 percent. the mass of b-10 is 10.013 amu.

Mass of B-11 = 11.009 amu

Explanation:

Given data:

Abundance of B-10 = 19.9%

Abundance of B-11 = 80.1%

Mass of B-10 = 10.013 amu

Mass of B-11 = ?

Solution:

Average atomic mass of boron is 10.811 amu.

Average atomic mass of boron =  (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

10.811 = (10.013×19.9) + (x × 80.1) /100

10.811 = 199.26 + (x × 80.1)

10.811 × 100 = 199.26 + (x × 80.1)

1081.1- 199.26 = x × 80.1

881.84 = x × 80.1

881.84/ 80.1 = x

x = 11.009

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

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.