In the last installment I discussed how atoms in Groups IA and IIA have only 1 and 2 e's in their valence shells respectively. These atoms satisfy the Octet Rule by losing those electrons to become +1 and +2 cations. On the other side of the periodic table, Groups VIA and VIIA have almost filled valence shells containing 6 and 7 e's respectively. One way these atoms can satisfy the Octet Rule is to take on 2 or 1 electron to become -2 or -1 anions. Ionic compounds are formed between at least one cation and one anion so that the substance formed is electrically neutral, held together by the electrostatic force of attraction between oppositely charged ions. Ionic compounds must contain at least one metal (cation) and one non-metal (anion).
Covalent compounds are bound by means of electron-sharing. Covalent compounds are formed from non-metals only.
Covalent compounds are bound by means of electron-sharing. Covalent compounds are formed from non-metals only.
