The atomic number of an element is 19.Is the element a metal or non-metal?

The atomic number of an element is 16.Is the element a metal or non-metal?

The atomic number of an element X is 20 while the atomic number of an element Y is 24.What is the nature of the bond formed between X and Y?Give the electron-dot structure of the compound formed.

Who showed that the atomic number of an element is a more fundamental property than its atomic mass and when?

Modern periodic tables is based on the atomic number of the elements . The experiment which proved the significance of the atomic number was

Name two solid non-metal .