Answer:
ATOMIC number of element A is 3
Explanation:
Atomic number is the same as number of protons of an element.
according to the periodic table, Lithium is the element with 3 protons in its neutral state and it's atomic number is 3.
Answer:
orbital
Explanation:
electrons are found in an orbital
The balanced chemical reaction is :

Number of moles of Na,
.
Now, from balance chemical reaction we can see that 1 mole of oxygen reacts with 4 moles of sodium.
So, number of moles of oxygen are :

So, amount of oxygen required is :

Therefore, 5.08 gram of oxygen will react with 14.6 gram of sodium.