Which of the following elements has properties different than the rest? (5 points) H
K
N
O

I think it is K.

Explanation:

It is has more gas than the others.

K

Explanation: K(Potassium) is actually a very weak metal that is usually in solid form. All of the other options(Hydrogen, Oxygen, and Nitrogen) are nonmetals that are usually gasses.

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