Will give brainliest for ! 1. the atomic radius increases from top to bottom because more orbitals are added as you go down a group. atomic radius decreases from left to right because there are more protons in each element as you go left to right, increasing the attractions between the protons and electrons, pulling the electrons in closer. a. true b. false

a. True

Explanation:

The atomic radius is taken as the half of the inter nuclear distance between two atoms that are covalently bonded.

Across a period, the atomic radii usually decrease progressively because the nuclear charge(number of protons in the nucleus) increases without the increase in the number of electronic shell. Therefore, the electrons are pulled more to the nucleus.

Down a group, the effect of the nuclear pull is reduced because the number of electron shell increases and the nuclear charge is being compensated for.

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally