For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
The cations and anions being oppositely charged attract each other through strong coloumbic forces and form an ionic bond.
(1) Sodium is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(2) Sodium is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(3) Sodium is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(4) Sodium is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(5) Potassium is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. They form .
(6) Potassium is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(7) Potassium is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(8) Potassium is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(9) Calcium is carrying +2 charge called as cation and chloride is an anion carrying -1 charge. They form .
(10) Calcium is carrying +2 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(11) Calcium is carrying +2 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(12) Calcium is carrying +2 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(13) Ammonium ion is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. They form .
(14) Ammonium ion is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(15) Ammonium ion is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(16) Ammonium ion is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(17) Iron is carrying +3 charge called as cation and chloride is an anion carrying -1 charge. They form .
(18) Iron is carrying +3 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(19) Iron is carrying +3 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(20) Iron is carrying +3 charge called as cation and carbonate is an anion carrying -2 charge. They form .
The observed brightness of a star (the apparent magnitude) to an absolute magnitude, you need to know the distance [d], to the star. Alternatively, if we know the distance and the apparent magnitude [m] of a star, we can calculate its absolute magnitude [d].
All what surrounds us, which has mass and occupies spaces, is matter. There are two kind of matter: pure substances and mixtures.
Pure substances have a uniform and constant composition. On the other hand, mixtures are combinations of two or more pure substances in any arbitratry ratio.
Pure substances may be elements or compounds. The elements are the substances conmposed by one only kind of atom. In the list of substances given, Li and O₂ are elements: all the atoms in Li are lithium, and all the atoms in O₂ are oxygen atoms.
Compounds are the chemical combination of two or more different kind of atoms. In the given list H₂O₂ and NaCl are compounds. As you see, H₂O₂ contains atoms of hydrogen and oxygen, chemically bonded, in a fixed ratio (2 atoms of hydrogen by 2 atoms of oxygen). And NaCl has atoms of Na (sodium) and Cl (chlorine), chemicaly bonded, in a fixed ratio (1:1).
There are only 118 known elements and you can find them in any modern periodic table. Therer are virtually infinitely many compounds since many different combinations of the elements can be attained.
Elements and compounds have in common that they are classified as pure substances.