Sodium fluoride reacts with hydroxyapatite to give fluorapatite according to the chemical reaction:
2naf + ca10(po4)6(oh)2 → ca10(po4)6f2 + 2naoh
i. name each ion in fluorapatite.
ii. indicate the charge on each ion in fluorapatite.
iii. show that the molecular formula for fluorapatite represents a neutral compound

We are given the balanced equation 2NaF + Ca10(PO4)6(OH)2 → Ca10(PO4)6F2 + 2NaOH. The fluorapatite is the product together with sodium hydroxide. The ions involved are (PO4) 3-, Ca 2+ and F-. We add the charges and check if the sum is zero, 2*10+-3*6+-1*2 =0. the zero sum tells that the compound has zero charge or neutral

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.