5 of 78

Valence Electrons

Valence electrons are the electrons in the OUTERMOST SHELL of the atom
Magnesium has _______ valence electrons
In order to be STABLE, atoms want to have either a FULL outer shell or EIGHT electrons in their outer shell
Magnesium would need to LOSE ____ electrons in its outer shell to become stable

9 of 78

Wednesday 10/25

BW: How many electrons would krypton want to gain/lose to become stable?

10 of 78

Formation of Ions

In neutral atoms, the number of protons and electrons are EQUAL
Electrons are frequently LOST or GAINED in chemical reactions and in static electricity
Key Idea: Only electrons in the VALENCE orbital can be lost/gained

11 of 78

Formation of Ions (Continued)

When an atom loses or gains an ELECTRON, it becomes CHARGED
Atoms with a net (total) charge are called IONS, and have DIFFERENT CHEMICAL PROPERTIES than non-ions
Atoms that GAIN electron(s) → ANION
Atoms that LOSE electron(s) → CATION

12 of 78

NET CHARGE = # Protons - # Electrons

13 of 78

Write the ion that is formed when Potassium (K) loses ONE electron

Ion:

Nuclide Symbol:

14 of 78

Write the ion that is formed when Chlorine (Cl) gains THREE electron

Ion:

Nuclide Symbol:

15 of 78

BW: Write the ion that is formed when Sulfur (S) gains 2 electron

Ion:

Nuclide Symbol:

16 of 78

Practice Problems

17 of 78

Write the ion that forms when Beryllium loses TWO electrons

Ion:

Nuclide Symbol:

18 of 78

Write the ion that is formed when Sulfur gains TWO electrons

Ion:

Nuclide Symbol:

19 of 78

Write the ion that is formed when Lithium loses FOUR electrons

Ion:

Nuclide Symbol:

20 of 78

Wednesday 10/25

BW: What was the pattern in valence electrons by group on the periodic table?

21 of 78

Number of Valence Electrons by Group Pattern

22 of 78

KEY IDEA: The last digit of group number tells you the number of VALENCE electrons (exception: Helium)

23 of 78

POGIL WS #10-11

24 of 78

Why do ions form the way they do?

25 of 78

Do you think Noble Gases form ions? Why or why not?

26 of 78

Common Ions in Nature

27 of 78

Draw an atomic model for Neon. What’s special about neon’s valence shell?

28 of 78

Common Ions by Family in the Periodic Table

29 of 78

Key Idea: Atoms are most stable when their VALENCE (outermost) orbital is full of electrons. To do so, atoms want to completely FILL or completely LOSE their outermost orbital of electrons

30 of 78

Friday 10/27

BW: How many electrons do the halogens gain/lose? What ion will Fluorine form?

31 of 78

Sodium Ion Formation (Group 1)

32 of 78

Sodium Ion Formation (Group 1)

33 of 78

Oxygen Ion Formation (Group 16)

34 of 78

Oxygen Ion Formation (Group 16)

35 of 78

Fluorine Ion Formation (Group 17)

36 of 78

Fluorine Ion Formation (Group 17)

37 of 78

Phosphorus Ion Formation (Group 15)

38 of 78

Magnesium Ion Formation (Group 2)

39 of 78

Tuesday 10/31

BW: Draw the atomic model of the ion Selenium forms. Write it’s ionic nuclide symbol

40 of 78

Ion Formation WS (Homework)

41 of 78

Wednesday 11/4

BW: How do you think Sodium (Na) and Chlorine (Cl) come together to make salt (NaCl)?

Sodium (Na) and Chlorine (Cl) come together to make salt (NaCl) through ionic bonding.

Here’s how it happens step-by-step:

Sodium (Na) has 1 electron in its outer shell. It wants to lose that electron to become stable.�
Chlorine (Cl) has 7 electrons in its outer shell. It wants to gain 1 electron to become stable.�
When sodium transfers its 1 outer electron to chlorine, both atoms reach full outer shells.�
Sodium becomes a positive ion (Na⁺), and chlorine becomes a negative ion (Cl⁻).�
These oppositely charged ions are attracted to each other, forming an ionic bond — this creates sodium chloride (NaCl), or table salt.�

In short: Sodium gives, chlorine takes, and their opposite charges pull them together to make salt.

42 of 78

Lewis Dot Structures

43 of 78

Draw Valence Electrons as Dots Around Symbol

44 of 78

Draw Lewis Dot Structure Practice

45 of 78

Draw Lewis Dot Structure Practice

46 of 78

Draw Lewis Dot Structure Practice

47 of 78

Draw the Lewis Dot Structures of Magnesium and Oxygen

Looking at the Lewis dot structures, how do you think Magnesium might form a chemical bond with Oxygen?

48 of 78

Ionic Bonding Reading

49 of 78

Thursday 11/2

BW: What are ionic bonds? How do they form between atoms?

50 of 78

Chemical Bonding

Because certain atoms want to GAIN electrons and others want to LOSE electrons, there is a perfect opportunity for a CHEMICAL BOND to occur
In a CHEMICAL BOND, electrons are GAINED, LOST, or SHARED between atoms

51 of 78

Forming Compounds (Table Salt)

After bonding, both atoms achieve FULL valence orbitals and are thus more STABLE than before
Chemical bonds between atoms are how new COMPOUNDS form. They have new PROPERTIES because they are more stable

52 of 78

Ionic Bonds

When atoms give or take electrons, the result is two IONS. But as a compound, they are all overall neutral
A bond in which electrons are FULLY GAINED/LOST is called an IONIC BOND
Ionic bonds always happen between a METAL and a NONMETAL

53 of 78

Sodium and Chlorine

54 of 78

Lithium and Fluorine

55 of 78

Sodium and Sulfur

56 of 78

How do you think Sodium and Sulfur can bond is Sodium has 1 valence electron, while sulfur has 6?

Let’s think this through step-by-step:

Sodium (Na) has 1 valence electron.
Sulfur (S) has 6 valence electrons.

Sulfur needs 2 more electrons to have a full outer shell (8 electrons total). Sodium, on the other hand, wants to lose its 1 valence electron to become stable.

Here’s how they can bond:

One sulfur atom needs 2 electrons.
Each sodium atom can give 1 electron.

So two sodium atoms will each transfer their 1 valence electron to one sulfur atom.

This forms the ionic compound sodium sulfide (Na₂S):

Each sodium atom becomes a Na⁺ ion (because it lost one electron).
The sulfur atom becomes an S²⁻ ion (because it gained two electrons).

In summary:� 2Na (each gives up 1 e⁻) → 2Na⁺� S (gains 2 e⁻) → S²⁻� → Na₂S

That’s how sodium and sulfur bond — by electron transfer forming an ionic bond!

57 of 78

Compounds and bonding can involve MORE THAN TWO atoms!

58 of 78

Common Ions by Family on the Periodic Table

59 of 78

Ionic Bonds Worksheet

60 of 78

Monday 11/6

BW: Draw the compound that is formed between Nitrogen and Hydrogen (Hint: it may require more than just 1 atom of each)

61 of 78

Tuesday 11/7

BW: Draw the compound that is formed between beryllium and chlorine (Hint: it may require more than just 1 atom of each)

62 of 78

What do you notice about the following molecules?

63 of 78

Wednesday 11/8

BW: Answer the following questions

How are covalent bonds different from ionic bonds?
Which types of elements typically form covalent bonds?
What are molecules?

64 of 78

Common Elements that Pair Up in Nature

How can two fluorines form a stable molecule?

65 of 78

Fluorine as a Covalent Bond

In a COVALENT bond, two atoms SHARE electrons
After bonding, both atoms achieve FULL valence orbital and are thus more STABLE than before

67 of 78

Covalent Bonding: Molecules vs. Compounds

Covalent bonds always occur between TWO NONMETALS (both want to GAIN electrons)

If the atoms that bond are IDENTICAL, the result is a MOLECULE
If the atoms that bond are DIFFERENT, the result is both a molecule and a COMPOUND

68 of 78

Practice Problem #1: Fluorine and Chlorine

69 of 78

Practice Problem #2: Oxygen and Sulfur

70 of 78

Practice Problem #3: Nitrogen and Phosphorous

71 of 78

Like ionic bonds, covalent bonds can also involve MORE THAN TWO atoms…

Oxygen + Fluorine + Fluorine

72 of 78

Thursday 11/9

BW: Draw the covalent bonding between oxygen and fluorine

73 of 78

Covalent Bonding WS

76 of 78

Friday 11/10

BW: Describe the difference between ionic and covalent bonding

77 of 78

Tuesday 11/14

BW: What are valence electrons? Explain how atoms become stable.

78 of 78

Thursday 11/16

BW: How many valence electrons does nitrogen have? How many does it want to gain/lose to be stable?

1 of 78

2 of 78

3 of 78

4 of 78

5 of 78

6 of 78

7 of 78

8 of 78

9 of 78

10 of 78

11 of 78

12 of 78

13 of 78

14 of 78

15 of 78

16 of 78

17 of 78

18 of 78

19 of 78

20 of 78

21 of 78

22 of 78

23 of 78

24 of 78

25 of 78

26 of 78

27 of 78

28 of 78

29 of 78

30 of 78

31 of 78

32 of 78

33 of 78

34 of 78

35 of 78

36 of 78

37 of 78

38 of 78

39 of 78

40 of 78

41 of 78

42 of 78

43 of 78

44 of 78

45 of 78

46 of 78

47 of 78

48 of 78

49 of 78

50 of 78

51 of 78

52 of 78

53 of 78

54 of 78

55 of 78

56 of 78

57 of 78

58 of 78

59 of 78

60 of 78

61 of 78

62 of 78

63 of 78

64 of 78

65 of 78

66 of 78

67 of 78

68 of 78

69 of 78

70 of 78

71 of 78

72 of 78

73 of 78

74 of 78

75 of 78

76 of 78

77 of 78

78 of 78