PLS HELP i will give 10 points In Mendeleev’s Periodic Table, why was there no mention of Noble gases like Helium, Neon and Argon?

Answer choices are:

A. These elements did not fit in with his pattern.

B. These elements are gases and he didn't include gases.

C. The atoms of these elements had no atomic mass.

D. These elements had not yet been discovered.

Correct answer choice is:

D. These elements had not yet been discovered.

i'm pretty sure it is letter c.) car

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.