Chemical Bonds 7.1.5

​Chemical Bonds 7.1.4
Notebook Page 136

​Name the elements that you see bonding above. Type them in the chat.

​Have your PTable up and ready to go!

​Today's lesson is FULL of information.
Please join the Wayground and have your notes ready to go.

​Subscript: a small number placed below the letters in a chemical formula

Valence Electrons: an electron in the outermost level of an atom that is involved in forming bonds


Atom: the smallest unit of a chemical element

Chemical Bond: attraction between atoms that forms a compound

Chemical Change: process that changes a substance into a new substance.

​The periodic table arranges elements according to their properties.
The chart consists of:

• rows called periods; and

• columns called groups.

​rows: left to right
columns: up and down

​Elements in the same period, or rows, have some properties in common. This diagram highlights period 4 of the periodic table.
All of the elements in this row have four energy levels of electrons.

​Potassium

​All of the elements in a group, or column, have similar properties to each other. This diagram highlights group 2 of the periodic table. These elements share these characteristics:

• metal

• soft

• reactive

​Notebook Page 136

Open Ended

Elements form new substances by creating chemical bonds. Recall that chemical bonds are attractions between atoms. Why do you think atoms form chemical bonds?

Match

Match the words to their definitions. Give it a try!

• valence electrons

• Lewis structures

• chemical formulas

• atoms

• nucleus

Electrons in the outer shell of an atom

Diagrams that show the bonding between atoms

Representations of the composition of a substance

The basic unit of a chemical element

The central part of an atom containing protons and neutrons

• Electrons in the outer shell of an atom

• Diagrams that show the bonding between atoms

• Representations of the composition of a substance

• The basic unit of a chemical element

• The central part of an atom containing protons and neutrons

​What are valence electrons?

Look at the image below and see if you can come up with a definition.

​A valence electron is an electron in the outermost energy level of an atom.

How many valence electrons do you see in each examples below? Count them first.

Then, open your PTable and see if you can make a connection between the group numbers and the valence electrons.

​Just so you know...

Groups 3-12 contain transition metals that follow special rules for valence electrons. You will not use elements from these groups in this course.

Lood at the YELLOW section to the left.

Multiple Choice

How many valence electrons does the atom have?

• 0

• 3

• 6

• 8

​Video in Edio, page 4

Multiple Choice

A neutral atom of chlorine contains 7 valence electrons.

How is chlorine most likely to satisfy the octet rule?

• Chlorine is most likely to lose 2 electrons.
• Chlorine is most likely to gain 3 electrons.
• Chlorine is most likely to gain or share 1 electron.
• Chlorine is most likely to share 2 electrons.

​8 legs on an octopus

​Atoms satisfy the octet rule by either gaining or losing electrons to make a complete outer shell.

• If the number of valence electrons is less than 4, the element will typically lose electrons.

• If the number of valence electrons is greater than 4, the element will typically gain electrons.

Atoms that gain or lose electrons form ions, or atoms with a positive or negative charge.

Poll

Will fluorine gain or lose electrons to become stable?

Count the valence electrons.

• gain 1

• lose 7

Poll

Will nitrogen gain or lose electrons to become stable?

• gain 3

• lose 5

Poll

Will potassium gain or lose electrons to become stable?

• it is stable!

Poll

Will magnesium gain or lose electrons to become stable?

• gain 6

• lose 2

Draw

Carbon is in group 14 of the periodic table. Remember that groups 13 through 18 have a number of valence electrons equal to the second digit of the group number. An atom of carbon has 4 valence electrons.

Place 4 dots to represent the valence electrons.

Draw

Fluorine is in group 17 of the periodic table, so it has 7 valence electrons.

Place the first 4 dots on separate sides of the symbol to represent valence electrons.

Place 3 dots in pairs to represent the remaining 3 valence electrons.

​Screenshot this!

​ Periods (Rows)

• go left to right (horizontal)

• 7 periods, each period = number of electron shells

• properties change across a period (metals to nonmetals)

  Groups (columns)

• go up and down (vertical)

• 18 groups, same number of valence electrons = similar properities

​Last Video of the Day! Edio Page 6