Physical Science

Ions and chemical bonds (ionic bonds and covalent bonds)

Essential Vocabulary

Define the following terms:





—Chemical bond

—Covalent bond

—Ionic bond

—Diatomic element

—Lewis dot

Recall valence electrons

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How to use Lewis Dot Notation

•Use the chemical symbol of the element.

•The dots represent the number of valence electrons (group #).

•Only 2 dots can be on each side.

•Always start with 1 dot on each side before pairing up dots.

•Does not matter which side you start pairing.

•Looking at Nitrogen’s lewis dot structure do you think nitrogen will want to lose 5 electrons or gain 3 to get a full outer shell of electrons? Which would be easier?

Practice together







Helium (the only exception to the rules)
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Your turn

—Complete the lewis dot structure for the following elements:







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—Atoms that gains or loses electrons.

—Positive ions lose electrons ~ less electrons than protons

—Negative ions gain electrons ~ more electrons than protons

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—Cations are Positive

(the t looks like a +)


—Loses electrons


—Metals (left side of periodic table)

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—Anions are Negative

(the n stands for -)


—Gains electrons


Non-metals (right side of periodic table)

Chemical bonds

—Bonds between atoms are created when electrons are paired up by being transferred or shared.

—A compound is formed when two or more kinds of atoms are bound together chemically.


—Two kinds of chemical bonds:



Ionic bonds

—Electrons are given up by the metal and taken by the non-metal.

—Their opposite charges cause them to remain close together.

—Usually between a metal (cation) and a non-metal (anion)

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Covalent bonds

—Electrons are shared between the two atoms.

—Stronger bond than ionic.

—Usually between two non-metals.

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Diatomic Molecules

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