Answer: Valence electrons are involved in a chemical reaction.
Explanation:
A chemical reaction takes place when there is an involvement of valence electrons. Bond formation involves either sharing of valence electrons or transfer of valence electrons. Bond breaking involves the separation of valence electrons.
When valence electrons are shared between the atoms, it leads to the formation of covalent bond.
When transfer of electrons takes place from one atom to another atom, it leads to the formation of ionic bond.
Hence, valence electrons are involved in a chemical reaction.
I think is A
Answer:
56°
Explanation:
First calculate 

The interplanar spacing can be calculated from:

The diffraction angle is determined from:

Solve for 

The diffraction angle is:

A protective layer composed of overlapping cells, like fish scales or roof tiles, but facing downwards. The outer cuticle holds your hair in your hair follicle by means of a Velcro-like bond. It also minimizes the movement of water (moisture) in and out of the underlying cortex.
There are 48.72 g Fluorine ions
<h3>Further explanation
</h3>
Proust stated the Comparative Law that compounds are formed from elements with the same Mass Comparison so that the compound has a fixed composition of elements
In the same compound, although from different sources and formed by different processes, it will still have the same composition/comparison
%F in CaF₂ :

mass of Fluorine :

So mass Fluorine ions(2 ions F in CaF₂⇒Ca²⁺+2F⁻) :
