What element is in period 2 and group 17?

(a)  

What element is found in period 7 and group 11?

(a)  

What element is found in period 5 and group 17?

(a)  

What element is found in period 2 and group 16?

(a)  

How many valence electrons does hydrogen have?

(a)  

How many valence electrons does boron have?

(a)  

How many valence electrons does calcium have?

(a)  

How many valence electrons does chlorine have?

(a)  

How many valence electrons does nitrogen have?

(a)