Explain what atom is used as a reference when determining how many atoms are in a mole

Ok so the MOLE (mol) is a unit of measurement representing the amount of a substance that contains the same number of atoms as there are molecules in exactly 12 grams of carbon-12 (i.e., 6022X1023).

Explanation: And that's how it goes, I hope you understood it well!

Best regards (Pr. El Haji)

1 a

2 d

3 a

4 c

explanation:

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.