*WILL GIVE A BRAINIEST & 15 POINTS TO THE CORRECT ANSWER* A sodium atom has the following electron configuration: 2-7-1-1. This is the excited state because the electron is moving from

A.) 4th shell to 2nd shell
B.) 2nd shell to 4th shell
C.) 3rd shell to 2nd shell
D.) 2nd shell to 3rd shell

2nd shell to the 4th shell

Explanation:it is in the excited state because the electrons have been moved to higher energy levels and do not fully fill the lower levels, as an atom in the ground state would, the second shell has moved to the fourth shell and not all 11 electrons are in their lowest energy level

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.