bohr models of ions. the purposes of the following notes are to help you: 1.learn to recognize the...

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Bohr Models of Ions

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Page 1: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Bohr Models of Ions

Page 2: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

The purposes of the following notes are to help you:

1. learn to recognize the difference between a Bohr model for an atom and a Bohr model for an ion.

2. understand why ions form in the predicable way as seen on the periodic table.

Page 3: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Changing Protons, electrons and neutrons

• We know that if we change the number of neutrons in an atom, we create a new isotope.

• We also know that if we change the number of protons in an atom , we create a brand new element.

• But what happens if we change the number of electrons in an atom?

Page 4: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Changing the electrons:

• Because protons are positive and electrons are negative, an atom with equal numbers of protons and electrons is “electrically neutral.”

• Having a different number of protons and electrons will produce something that is no longer electrically neutral. It can no longer be called in atom.

• Now it will be called an ion.

Page 5: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Comparing protons and electrons

(12 protons) + (12 electrons) =_________

(12 protons) + (11 electrons) =_________

(12 protons) + (13 electrons) =_________

“neutral Atom”0

+1 “Positive ion”

-1 “negative ion”

Page 6: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

But why do elements form ions?

• To answer this we must look at the noble gases.

Page 7: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

The Noble Gases

• He

• Ne

• Ar

Page 8: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Noble Gases are “cool.”

• Noble gases have the perfect number of electrons…that is they have a full outer shell or valence shell

• All the other atoms have not enough electrons or too many electrons.

• As a result, all of the other elements spend their time trying to imitate the “cool” noble gases by getting rid of or by chasing after extra electrons from other atoms.

• When atoms gain or lose electrons they become ions.

• Noble gases, since their valence shells are filled, don’t react with other elements and are said to be inert. Thus they will not form ions.

Page 9: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 1: Metals

A) Lithium (Li)

Lithium wants to give away 1 electron and look like Helium.

If it does, it will turn into a Li+1 ion.

Page 10: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 1 Metals:

B) Magnesium (Mg)

Magnesium wants to lose two electrons and look like Neon.

If it does it will turn into a Mg+2 ion.

Page 11: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Metal ions

• All metals need to lose one or more electrons to become “cool” which means they will always form Positive ions called cations. LEP

Page 12: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 2: Non-metals

A) Fluorine (F)

Fluorine wants to gain one electron to look like neon

If it succeeds, it will turn into a F-1 ion

Page 13: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 2: Non-metals

B) Phosphorus (P)

Phosphorus wants to gain 3 electrons to look like Argon.

When it does, it will become a P-3 ion.

Page 14: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Non-metals

• All non-metals need to pick up one or more electrons to be cool like the noble gases. Thus they always form negative ions called anions.

• GEN: Gain Electrons=Negative

Page 15: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise:

1) Determine the type on ion that each of the following atoms wants to form

a) Al → Al+3 (positive ion)

b) Be

c) O

d) Br

e) Na

Page 16: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise:

• When a METAL meets a NON-METAL they form an Ionic Bond

A) When Na meets F:

Na wants to give away 1 electron and become Na+1.F wants to take away 1 electron and become F-1.They exchange electrons and are now “cool” and they have

opposite charges and opposite charges cancel.

Page 17: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise

B) When Mg meets O

Page 18: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise:

C) When Mg meets F:

Page 19: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise:

D) When Al meets Cl:

Page 20: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Exercise:

D) When K meets S:

Page 21: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Assignment:

• WB p63-64 Q# 1-14, 16

• Quiz next class: Bohr models of atoms vs ions.

Page 22: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Ionic Compounds

Page 23: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Writing Ionic Compound Formulas:

A) Binary Compound: a compound with only two types of elements in an ionic bond (metal and non-metal)

Step 1: Metal is written first, non-metal is written second

Step 2: Write the combining capacities (or charge) beside each ion as a superscript.

Step 3: Flip flop the combining capacities for each element and remove the charges (signs +/-) from subscripts.

Step 5: reduce the subscripts and remove any “ones”

Page 24: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Assignment:

• Text p 188 practice problems 1 and 2

Page 25: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Naming Ionic Compounds

Step 1: Metal name stays the same and is written first

Step 2: Non-metal name is written second and ends with “ide”

Page 26: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Write the chemical name:

1) NaClSodium Chlorine →remove the “ine” from chlorine

→add the “ide” to Chlor___.

Becoming: Sodium Chloride

Page 27: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

2) MgF2

Write the chemical name:

Page 28: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Write the chemical name:

• K+1 and S-2

Page 29: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Assignment:

• Text p 187 practice problems 1a-o

Page 30: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

B) Elements with more than one combining capacity:

How do you recognize these elements? Elements on the periodic table that have more than one charge

• Roman numerals are included in the names of these ionic compounds to show the charge of the metal ionmetal ion.

• Examples: I, II, III, IV, V,

Page 31: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 1:

• Write the name for• FeCl2

1. Check for metal and nonmetal

2. Check for multiple combining capacity

• If yes: use roman numerals in name

• If no: no roman numerals in name

3. Reverse flip flop

4. Check nonmetal charge

5. Write name

(metal (RN) non-metal-”ide”)

Page 32: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 2:

• Write the name for

• FeCl3

Page 33: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Assignment:

• Text p 190 and 191 practice problems

Page 34: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

C) Charged Groups of Atoms:AKA Polyatomic ions

Groups of atoms that tend to stay together and carry an overall charge .

How do you recognize them in a formula for a compound? Recognized by three or more capital letters in a formula of a compound

• Polyatomic ions are treated as a single ion• See data booklet sheet

Page 35: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Formulas: If two or more polyatomic ions occur in a compound, then the chemical formula for the polyatomic ion is enclosed in parenthesis

Naming: the names of polyatomic ions stay as they are seen in the data booklet. No changing of the ending is needed.

C) Charged Groups of Atoms:AKA Polyatomic ions

Page 36: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Example 1:

• Write the formula and name for

• Ca+2 and OH-1

Page 37: Bohr Models of Ions. The purposes of the following notes are to help you: 1.learn to recognize the difference between a Bohr model for an atom and a Bohr

Assignment:

• Text p193 practice problems