1
Chlorine is the member of the halogens family; the electrical charge of the chloride ion (Cl-) is -1.
Mg-24
That it does not gain or loose electrons.
They indicate groups of elements which often (but not always) share common properties. (cf. http://en.wikipedia.org/wiki/Periodic_table#Groups)One of the common characteristics in a group is that they share the same number of electrons on the outer shell.
No, it is a compound, not a mixture. Its formula is MgO, and it contains Magnesium and Oxygen (two fairly common elements).
A Magnesium ion has a charge of 2+.
Phosphorus is number 15 on the Periodic Table of Elements. The most common charge is -3 because it needs three more electrons to fill it's outer shell.
Chlorine is the member of the halogens family; the electrical charge of the chloride ion (Cl-) is -1.
A+ (+2)
Calcium
Beryllium and magnesium are members of the group 2 of the Periodic Table - alkali earth metals.
Mg-24
-2
-2
Elements listed in the periodic table of elements are neutral; they do not have a charge. When they undergo chemical reactions they may become charged ions. There is no single most common charge for ions, but the most common are -1, -2, -3, +1, +2 and +3.
They don't have a negative charge. That is a common misconception.
That it does not gain or loose electrons.