*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

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.