Answer:
The symbol of each element is, Ne, Na, Mg, and Al.
Explanation:
Below is the list of elements that has an atomic mass of less than 19.3 u.
The atomic mass of Neon is 20.1797 u and the atomic number is 10.
The atomic mass of Sodium is 22.989769 u and the atomic number is 11.
The atomic mass of Magnesium is 24.305 u and the atomic number is 12.
The atomic mass of Aluminium is 26.981539 u and the atomic number is 13.
Here, the symbol of each element is, Ne, Na, Mg, and Al.
<span>Atomic radius generally increases as we move
</span><span>down a group and from right to left across a period.</span>
Answer:
Explanation:
As given in the question that methane(
) is taken excess amount
mass of 
depend only on mass of fluorine
mass of 
=180 g
mole of =
=9.47
3 mole of gives 1 mole of
so 1 mole will give 
mole of
therefore,
9.47 mole of will give 
mole of
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