Answer:
One positive charge
Explanation:
In a neutral atom, the number of positive and negative particles are equal. This leaves the atom with a net charge of zero, 0.
When the number of protons in an atom is greater than the number of electrons, the atom becomes positively charged. When an atom loses an electron when a bond wants to form, it has a net positive charge.
The number of electrons lost or gained determines the charge.
The Law of Conservation of Matter states that matter cannot be created or destroyed. In a physical change, substances can change form, but the total mass remains the same.
There are 5.43 x 10²³ present in 187 grams of XeF₄
<h3>Further explanation </h3>
The mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass

mass of XeF₄ = 187 g
mol XeF₄ (MW=207,2836 g/mol) :

Number of molecules :

0.5 mole of Mg=12 grams= 0.5x atoms
Final or new substances in a chemical equation will be called PRODUCT!. hence the substances itself are reactants. hope it helps a bit.