Answer:
It gives the number of protons in the nucleus of each atom of that element. 
Explanation:
 
        
             
        
        
        
Answer:
15.5 gm
Explanation:
What is the mass of phosphorus that contains twice the number of atoms found in 14 g of iron?
[Relative atomic mass : P = 31; Fe = 56]
14 gm Fe = 14gm/ 56 gm/mole = 14 mole gm/56gm = 14/56 mole
0.25 moles
2 X 0.25 = 0.5 moles
1 mole P = 31 gm
so
0.5 moles P =31/2 =15.5 gm
 
        
             
        
        
        
I would think the last one about the ozone layer
        
             
        
        
        
In Lewis dot structures, you draw the atom in the center and then surround the atom with its valence electrons. The Lewis structure for O is as shown in the attached diagram.
<h3>What is the Lewis structure of O ?</h3>
Lewis Structure of an atom of oxygen contains 6 electrons in the valence shell. Four valence electrons exist in lone pairs. It implies that oxygen atom must participate in two single bonds or one double bond in order to have an octet configuration.
A simplified representation of the valence shell electrons in a molecule  is called Lewis Structure. It shows how electrons are arranged around individual atoms in the molecule.
To know more about Lewis structure, refer
brainly.com/question/1525249
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