Answer:
The answer would be Point of Reference.
In order to determine, whether an object has moved or not, a point of reference is required. The reference point is required to the measure the movement of the object, without a reference point the distance or displacement cannot be obtained. Hence, a reference point is very required to determine, whether the object has moved or not.
(Hope this helps) Sky
Fluoride is an anion of Fluorine
What this means is that the two have the same number of protons (9), but Fluoride has 10 electrons compared to Fluorine's 9.
So the answers are:
Protons - 9
Neutrons - 9
Electrons - 10
Atomic Number - 9
Atomic Mass - 19 g/mol