22.2 Notes – Types of Bonds

Objective

Describe ionic and covalent bonds. Identify the particles produced by ionic

bonding and by covalent bonding.

Ion

An atom that has lost or gained electrons A charged particle because it has

more or fewer electrons than protonsAtoms lose or gain to meet a

standard—a stable energy level

How bonds formThe positive and negative

charges are not balanced on their own

It is the electric forces between oppositely charged particles that hold compounds together

A Bond Forms - KIA neutral atom of potassium has

one electron in its outer level Not a stable outer energy level

Potassium often forms compounds with halogens Alkalis (Group 1) often form

compounds with Halogens (Group 17 / 7A)

Ion = K+ Loses an electron (drops one

energy level), becomes positively charged

One less electron in the atom than protons in the nucleus

The 1+ charge is shown as a superscript written after the element’s symbol to indicate its charge

Iodine atom also undergoes a change Iodine has 7 electrons in its outer

energy level Iodine atom wants to gain an

electron to fill its outer energy level

No longer neutral because it has gained an extra negative particle

Has a charge of –1 and is called a iodide ion, written as I-

Potassium iodide

Cation = positive ionLoses electrons

Anion = negative ionGains electrons

Ionic Bonds

When ions attract due to their opposite charges

In an ionic bond a transfer of one or more electrons takes place and large amounts of energy are released If an element loses electrons, one or more

elements must gain an equal number of electrons to maintain the neutral charge

http://www.youtube.com/watch?v=c-nMmwfTV-w

Formation of Ionic Bond

Magnesium reacts with chlorine Magnesium atom loses 2 electrons and becomes

a positively charged ion, Mg2+

Two chlorine atoms gain one electron each and become negatively charged ions, Cl-

Ionic Bonds

Zero net charge = Neutral compound Positive charge balances with negative

charge

Metal + nonmetalElements on opposite sides of periodic

table

In-class Assignment/homework

Get out learning target inventory and under a column yourself on objectives #1-5 and Muddiest Point

22.1 & 22.2 Directed reading WKT