Question

Please help!!!!!!!!!!!!

Answer 1

Answer:

The answer to your question is below:

Explanation:

1.-  Atomic number, elements in the periodic table increase their atomic number from left to right.

2.- A weighted average of the masses of an element's isotopes.

3.- Most metals are brittle, Metals are not brittle, Non metals are brittle.

4.- Most reactive nonmetals, that is because halogens have 7 valence electrons that means that only need one electron to be stable.

5.- Amu, is the abbreviation of Atomic mass unit.