Chapter 6 - Ionic and Molecular Compounds

The stable electron arrangements in the outermost energy level are associated with the stability of the noble gases.
Noble gasses have eight valence electrons, which is an octet, except for helium, with two electrons.
In Groups 1A to 7A (1,2, 13 to 17), the atoms of elements achieve stability through loss, gain, or sharing in the formation of composites their valence electrons.
Representative metals lose valence electrons to make positive ions (cations): Group 1A, Group 1+, Group 2A(2), Group 2+ and Group 3A(13), Group 3+.
In response to metals, nonmetals gain electrons to form bytes that form negative ions (anions): group 5A (15), group 3-, group 6A (16), group 2- and group 7A (17), group 1-.

In the formula of an ionic compound, the total positive and negative ionic load is balanced.
A formula charging balance is achieved using subscripts after every symbol so that the total charge is zero.

The positive ion is first indicated by its name, followed by the negative ion name.
Two element names of ionic compounds end with ide.
The transition elements form cations with two or more ionic charges, apart from Ag, Cd, and Zn. * The cation's charge is determined by the total negative charge in the formulation, which is immediately named after the metal with a variable charge as a roman number.

A Polyatomic ion is a group of electrically load-bound, covalent atoms, such as the formulation CO3 2- for the carbonate ion.
The names that end with ate or are mostly polyatomic ions. * A nonmetal and one or more atoms contain polyatomic ions.
The NH4+ ammonium ion is a polyatomic positive ion
If several polyatomic ions are used to balance the charge, parentheses include the polyatomic ion formula.

Non-metals share valence electrons in covalent bonds, which ensures that every atom has a stable electron set-up. * In a molecular compound, the first nonmetal uses its name; the second nonmetal uses the first syllable of its name, followed by the ideal element.
The name of a two-atoms-molecular compound uses prefixes to indicate the subscriptions in the formulation.

For all the atoms in the molecule, the total number of valence electrons is determined.
In Lewis's structure, the central atom and each of the attached atoms is connected by a pair of electrons.
All remaining valence electrons are used to complement the octets of the surrounding atoms and the central atom as solitary pairs.
If octets are not completed, one or more lone electron pairs are placed as double or threefold connecting pairs

Electronegativity is an atom's ability to attract electrons that it shares. * The electronegativity of metals is generally low, while nonmetals have high electronegativity.
Atoms share electrons equally in a nonpolar covalent bond.
The electrons are unequally divided into a polar covalent connection because they are attracted to the more electronegative atom.
The atom is partly positive in a polar relationship (d+) and partly negative in the polar link with lower electronegativity (d+) (d-).
Atoms forming ionic bonds differ greatly in electronegativity.

The shape of a molecule is based on the Lewis structure, the geometry of the electron group and the number of atoms connected. * The geometry of the electron group surrounding a central atom with 2 electron groupings is linear; the geometry is planar trigonal in three electron groupings, and geometry is tetrahedral in four electron groups.
The shape is identical to the electron arrangement when all of the electron groups are attached to atoms.
A central atom has a bending form of 120° with three groups of electrons and two bonded atoms. * There is a trigonal pyramid shape in a central atom with four different electron groups and three connected atoms.
A central atom has a curved form at 109°, consisting of four electron groups and two bonded atoms.

Non-polar molecules have non-polar covalent links or a bonded atomic arrangement to waive dipole
The dipoles do not cancel in polar molecules * Opposite loaded ions are held in ionic solids by ionic connections in a rigid structure.
Intermolecular forces are known as dipole-dipole and hydrogen binding maintained together with the solid and liquid states of polar molecular compounds. * The weak attractions between temporary dipole known as dispersion forces form nonpolar compounds.