A material will change from one state or phase to another at specific combinations of temperature and surrounding pressure. Typically, the pressure is atmospheric pressure, so temperature is the determining factor to the change in state in those cases.
Names such as boiling and freezing are given to the various changes in states of matter. The temperature of a material will increase until it reaches the point where the change takes place. It will stay at that temperature until that change is completed.
The amount if protons is the same as the amount of electrons, so it would be 8. The charge is -2. Look at oxygen in the periodic table.
The oxidation is occurring on Calcium ions as it release one electron and reduction will be occurring on fluorine ion as it accepts one electron.
<u>Explanation:</u>
An element will undergo oxidation and form a positive ion on releasing one or more electrons from its valence shell. While reduction is occurred in a chemical reaction, then the element will be forming a negative ion with the acceptance of one or more electrons in its valence shell.
So in the given process of calcium fluoride, the one electron from the valence shell of calcium will be released making it as
ions and this is termed as oxidation process. This one electron will be getting accepted by the fluorine ion and thus it will convert to
ions. This process of acceptance of electrons is termed as reduction.
Elements in the same group on the periodic table have the same number of valence electrons. The "groups" are the column (or rows). groups are vertically and periods are horizontally.