8/2/2019 Chapter 8 Section 1 - Electrons and Chemical Bonding

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Chapter 8 Section 1: Electrons and Chemical Bonding Ellin ZhaoPer. 12/06/12

Key Concept: Atoms share, gain, or lose electrons when chemical bonds form.

Define chemical bonding.

How do new substances formed from bondingdiffer from the original element?

Define chemical bond.

Combining Atoms Through Chemical Bonding- Everything is made of atoms of

elements.- Atoms of different elements combine

in different patterns.- Chemical bonding is the joining of

atoms to form new substances.- Properties of the new substances are

different from the properties of theoriginal elements.

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An interaction that holds two atomstogether is called a chemical bond

Discussing Bonding Using Models- Atoms are very complex so we use

models to discuss how and why atomsform bonds.

- Simple models that are used to discusselectrons in an atom dont show all thedetails of the structure of the atom orchemical bond.

PS1:The results of chemical bonding form new substances that have different properties than theoriginal elements. Chemical bonds form when electrons are shared, gained, or lost.

Define valence electron.

Electron Number and Organization- The atomic number tells you the

number of protons and electrons in anatom.

- Models do not show the true structureof atoms.

Outer- Level Electrons and Bonding- Most atoms form bonds only in the

outermost energy level.- An electron in the outermost energy

level in an atom is a valence electron.

Valence Electrons and the PeriodicTable

8/2/2019 Chapter 8 Section 1 - Electrons and Chemical Bonding

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- You can use the periodic table to findthe number of valence electrons.

- Atoms in the same family have thesame number of valence electrons.

PS2:

A valence electron is an electron in the outermost energy level of an atom. Atoms that have thesame number of valence electrons are grouped in the same families on the periodic table.

Why do some atoms not bond?

How do atoms bond with other atoms?

To Bond or Not To Bond- Not all atoms bond in the same way.- Atoms of noble gases (Group 18) do

not usually bond.- Atoms that have eight electrons in

their outermost level are nonreactive.

Filling the Outermost Level

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Atoms that have fewer than eightvalence electrons usually form bondsby gaining, losing, or sharing electrons.

Are Two Electrons a Full Set?- Helium only has two electrons so the

energy level is already full.- Also form bonds by gaining, losing, or

sharing electrons.PS3:Some atoms dont bond because their outermost levels are filled. Atoms form bonds when theygain, lose, or share electrons until they have eight valence electrons.Summary:Atoms share, gain, or lose electrons when chemical bonds form. The results of chemicalbonding form new substances that have different properties than the original elements.Chemical bonds form when electrons are shared, gained, or lost. A valence electron is anelectron in the outermost energy level of an atom. Atoms that have the same number of valence electrons are grouped in the same families on the periodic table. Some atoms dontbond because their outermost levels are filled. Atoms form bonds when they gain, lose, orshare electrons until they have eight valence electrons.