im doing 9th grade Basic Science i dont understand this chapter we're doing Chemical Formulas. can you help?

Question

i don't understand oxidation numbers writing formulas polyatomic ions or chemical formulas. Can any one please help me!!!

Answer 1

Oxidation numbers: tell which atoms lose or gain electrons in chemical reactions, they can be determined by electronegativity

This web-site lays it out for you and gives examples.

http://st19.startlogic.com/~honorsph/honorsphysicalscience/chemical%20formulas/writing_formulas.htm

Answer 2

. n_hall_22 is right. The oxidation number is the number of electrons an atom can "give up" or "accept" when forming a compound with another atom. If the atom has just one electron in its outer "shell" (its not really anyhing at all like a shell, or orbit) it is more likely to have that electron sort of fill in another atoms outer shell than it is to fill all of the available spots in its outer shell. It would be considered that this atom "gave up" its electron to another atom. If an atom has an outer shell with 7 electrons in it, it sort of has an opening in its outer shell, and is more likely to accept an electron than to give any up. Calcium has an outer shell with only 2 of 8 possible electron positions filled. It is very likely to loan its outer 2 electrons to one atom with 6 out of 8 of its electron positions filled, or one each to two atoms which have 7 out of 8 electron positions filled. This tendency to give up or accept electrons become less for atoms which come closer to having half of their electron positions filled. Those atoms, like carbon or silicon, are more likely to share electrons evenly with other atoms than to give them up.
. Now, in most cases, those atoms do not truly give up their electrons. Between them and the atoms they are compounded with, they have all of their electrons, and the molecule is electrically neutral. Sometimes though, outside influences can cause some of the electrons to be driven away from the molecule, or extra electrons can become associated with the molecules. These molecules are then "ionized" which just means that they are not electrically neutral. Some of the influences which can cause ionization are the exposure to an electric field, or a very fast subatomic particle (ionizing radiation) zipping through and knocking electrons or protons out of the molecule. Some molecules also dissolve in water in such a way that the molecules split apart into ionized molecules. H2SO4 will dissolve into two molecules, one with a positive charge and one with a negative charge. The solution, called sulfuric acid, is very reactive because of its ionized molecules.
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Answer 3

Oxidation numbers are the number of electrons an element is able to accept or give away