Ionic compounds When an atom gains or loses electrons, the atom is no longer neutral. It has become an ion. An ion has either a positive or a negative charge. Ions do not have an equal number of protons and electrons like atoms do.
Sodium atoms can become ions When a sodium atom (a metal) loses an electron, it becomes a sodium ion. It has an overall positive charge and it no longer has its original properties.
Chlorine atoms can become ions When a chlorine atom (a non-metal) gains an electron, it becomes a chlorine ion. It has an overall negative charge and no longer has its original properties.
Na+ and Cl- attract each other Because Na+ and Cl- are oppositely charged, they will attract each other and form an ionic compound. NaCl has very different properties than either sodium or chlorine as neutral atoms.
Ionic compounds conduct electricity
Naming molecular compounds
Naming molecular compounds Chemistry is done all over the world To avoid confusion, scientists have come up with a universal way to name chemical compounds The group that is in charge of setting standards for naming chemical compounds is called the International Union of Pure and Applied Chemistry (IUPAC)
IUPAC naming rules for molecular compounds 1. Write the entire name of the first element 2. Change the ending on the name of the second element to ide 3. Use a prefix to indicate the number of each type of atom in the formula: 1 = mono* 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa * Mono is only used for the second element in the compound
Examples 1. Write the entire name of the first element 2. Change the ending on the name of the second element to ide 3. Use a prefix to indicate the number of each type of atom in the formula: 1 = mono* 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa * Mono is only used for the second element in the compound 1. H₂O is named dinitrogen monoxide 2. NO is named nitrogen monoxide 3. NH 3 is named nitrogen trihydride
CCl₄ Carbon tetrachloride
N 2 O₄ Dinitrogen tetraoxide Apollo-Soyuz Test Project 1975 https://en.wikipedia.org/wiki/apollo%e2%80%93soyuz_test_pro ject
H 2 S sour gas Working on the side of a volcano
Writing the chemical formula from the name If you are changing from the written name of the compound to the formula: 1. Write the symbols for the elements in the same order as they appear in the name 2. Use subscripts to indicate the numbers of each type of atom Examples: 1. What is the chemical formula for dinitrogen monoxide? N 2 O 2. What is the chemical formula for silicon dioxide? SiO 2 3. What is the chemical name for phosphorus trichloride? PCl 3
Naming binary ionic compounds
Naming binary ionic compounds Two rules for naming binary ionic compounds: 1. The first element in the name and formula is the metal 2. The second element, the non-metal, is named as an ion. In other words, the suffix -ide is attached to the name. Example: the compound formed from lithium and fluorine is named lithium fluoride
Examples The compound formed from sodium and chlorine is named sodium chloride The compound formed from magnesium and nitrogen is named magnesium nitride
You try The compound formed from magnesium and oxygen is named? magnesium oxide The compound formed from lithium and bromine is named? lithium bromide The compound formed from beryllium and phosphorus is named? beryllium phosphide
Review: formulas for binary ionic compounds The chemical formula shows the simplest whole number ratio of each type of ion in the compound. Example: the formula CaF₂ indicates that any crystal of calcium fluoride contains two fluoride ions for every one calcium ion (2:1 ratio of fluorine to calcium)
Review: formulas for binary ionic compounds To determine the formula for any binary ionic compounds, use the periodic table to determine the number of transferred electrons between the two elements. For groups 1, 2, and 13-18 you can use the group number to determine the common charge
Create a Venn diagram for naming molecular and ionic compounds