How does an atom of lithium form an ionic bond with an atom of chlorine?
Atoms are particles with an overall charge of zero - uncharged particles. Learn this rule: Metal atoms lose electrons (-) to become positively charged ions (+). No-metal atoms gain electrons (-) to become negatively charged ions (-). Rule No2. = 2,8,8. What does this mean? The first shell contains a MAXIMUM of 2 electrons, 2nd shell contains a MAXIMUM of 8 electrons, and the 3rd shell contains a MAXIMUM of 8 electrons. When the shells of atoms are fully occupied by the maximum number of electrons, they are "happy" and stable. Why do atoms become ions? To gain stability. Rule No 3: Group number tells you how number of electrons in the last shell of an atom. Rule No 4: The period number tells you how many shells the atom has. Apply the rules! The element lithium found in group 1 (one electron last shell) and period 2 (2 shells). Each atom in an element of lithium has one electron in its last shell (2nd shell). A lithium atom loses this one electron, the 2nd shell becomes empty so the first shell is now the last shell. Remember the first shell contains 2 electrons and is stable. Lithium atom has lost an electron to become a positively charged ion, with a charge of +1. The element chlorine is found in group 7. Each atom in an element of Fluorine contains 7 electrons in its outer shell. Found in period 3, so it is the 3rd shell contains 7 electrons. I'm sure you can agree with me when I say it is harder to lose 7 electrons, but easier to gain one electron to become stable. Fluorine receives this electron that was given away by the lithium atom. This fluorine atom becomes a fluoride ion with a charge of -1. We have formed two oppositely charged ions. The Lithium atom has become a positive ion and chlorine atom has become a lithium ion. Rule No.5: Opposites attract. Positively charged Lithium ions form an ionic bond with negatively charged Fluoride ions. They are held together by this strong force of attraction because opposites attract.
Lithium ‘loses’ its valence electron and forms a positive lithium cation. Chlorine ‘gains’ that electron and forms a negative chloride anion. The opposite charges form an electrostatic attraction which is the ionic bond.
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