Which of the first 20 elements in the periodic table are metal and which are non-metals?

First 20 elements in periodic table which are:-

Metals:

• Lithium$\left(\mathrm{Li}\right)$
• Beryllium$\left(\mathrm{Be}\right)$
• Sodium$\left(\mathrm{Na}\right)$
• Magnesium$\left(\mathrm{Mg}\right)$
• Aluminium$\left(\mathrm{Al}\right)$
• Potassium$\left(\mathrm{K}\right)$
• Calcium$\left(\mathrm{Ca}\right)$

Non-Metals:

• Hydrogen$\left(\mathrm{H}\right)$
• Helium$\left(\mathrm{He}\right)$
• Carbon$\left(\mathrm{C}\right)$
• Nitrogen$\left(\mathrm{N}\right)$
• Oxygen$\left(\mathrm{O}\right)$
• Fluorine$\left(\mathrm{F}\right)$
• Neon$\left(\mathrm{Ne}\right)$
• Phosphorus$\left(\mathrm{P}\right)$
• Sulfur$\left(\mathrm{S}\right)$
• Chlorine$\left(\mathrm{Cl}\right)$
• Argon$\left(\mathrm{Ar}\right)$