Chlorine is an active non metal. why?

Explanation:

The electronic configuration of chlorine is. As there are only five electrons in 3p sub shell therefore, in order to obtain stability, chlorine requires to gain only one electron. Therefore, it will react readily with another element who can transfer or share one electron. That is why, chlorine is an active non-metal

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles