Answer:
We know based on the charges of each ion and the fact that they must always sum to 0
Explanation:
Na only has one outer electon to give so it is always +1
Mg has two outer electrons so it always gets +2
Halogens have one "missing" electron in their outer shell so they get a -1
For NaCl (+1) + (-1) = 0
For MgI2 (+2) + 2(-1) = 0
Answer : The chemical formula for the compound is, 
Explanation :
When the element 'M' react with the 
to give .
The balanced chemical reaction is,
In this reaction, 'M' is in mono-atomic form and is in diatomic form.
By the stoichiometry,
2 moles 'M' react with the 1 mole of to give 2 moles of .
Therefore, the chemical formula of the compound is,
She must have used the torch as Sun, the tennis ball as Earth and the marble as Moon.
Answer: Depending on the state of change it can be a physical change. Example: Evaporation is the physical change of a liquid turned into a gas.
That said, I'm pretty sure the answer is (True)
Note: Hope this is correct and it helps. Good luck :)
Valence.
The electrons in the outer shell of an atom are called valence electrons.
Valence electrons determine whether the an element is ready form compounds. These electrons can be gained, lost, or shared in the formation of compounds.
