valence electrons valence electrons are the electrons in the highest occupied energy level of an...
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Valence Electrons
Valence electrons are the electrons in the highest occupied energy level of an element’s atoms.
Electron dot structures are diagrams that show valence electrons as dots.
Valence Electrons
The Octet Rule
The octet rule states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas.
Formation of Cations
Formation of Cations
Formation of Anions
Formation of Anions
Formation of Ionic Compounds
Compounds composed of cations and anions are called ionic compounds.
Formation of Ionic Compounds
A chemical formula shows the kinds and numbers of atoms in the smallest representative unit of a substance.
A formula unit is the lowest whole-number ratio of ions in an ionic compound.
Molecules and Molecular Compounds
Atoms held together by sharing electrons are joined by a covalent bond.
A molecule is a neutral group of atoms joined together by covalent bonds.
A diatomic molecule is a molecule consisting of two atoms of the same type.
Molecules and Molecular Compounds
A compound composed of molecules is called a molecular compound.
Molecular Formulas
Single Covalent Bonds
Two atoms held together by sharing one pair of electrons are joined by a single covalent bond.
Single Covalent Bonds
A pair of valence electrons that is not shared between atoms is called an unshared pair.
Single Covalent Bonds
Double and Triple Covalent Bonds
A bond that involves two shared pairs of electrons is a double covalent bond.
A bond that involves three shared pairs of electrons is a triple covalent bond.
Binary Ionic Compounds
A binary compound is composed of two elements and can be either ionic or molecular.
To name any binary ionic compound, place the cation name first, followed by the anion name.
SnF2 = tin(II) fluoride
SnS2 = tin(IV) sulfide
Fe2O3 = iron(III) oxide
MgO = magnesium oxide
NaCl = sodium chloride
Al2S3 = aluminum sulfide
Compounds with Polyatomic ions
To write formulas for compounds with polyatomic ions, write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges.
To name a compound containing a polyatomic ion, state the cation first and then the anion just as you did in naming binary ionic compounds.
Naming Binary Molecular Compounds
A prefix in the name of a binary molecular compound tells how many atoms of an element are present in each molecule of the compound.
Naming Binary Molecular Compounds
1. Confirm the compound is binary molecular – a compound composed of two nonmetals.
2. Name the elements in the order listed in the formula. Use prefixes to indicate the number of each kind of atom.
3. The end of the name of the second element is always changed to –ide.
Writing Formulas for Binary Molecular Compounds
Use the prefixes in the name to tell you the subscript of each element in the formula. Then write the correct symbols for the two elements with the appropriate subscripts.