DUE NOW (10 MINUTES) Warm-ups (9/8 – 9/11) [4 total]

Homework #9 & Homework #10

Classwork: 5 PRACTICE PROBLEMS (Converting moles/grams)

Chapter 3 Study Guide

ATOMIC ZOOAnimal Name

Element NamesComposed Of?

Atomic # Cage #

Atomic Mass (total) Weight

LiON Li -Lithium O -OxygenN -Nitrogen

Li –3 O - 8N- 7

6.94 16.00 14.01TOTAL: 36.95

BeAr Be- BerylliumAr- Argon Please complete 10 (15

E.C.)

WARM-UP (9/15/14) Draw the Bohr model of an atom. What was the main feature of this model?

PERIODIC TABLE How is the periodic table organized?

Vertical column = groupHorizontal row = period

BOHR’S MODEL & ELECTRONS

Electron shells surround the nucleus and each hold a certain number of electrons

1. First shell holds 2 electrons2. Second shell 8 electrons3. Third shell 18 electrons

THE OUTER SHELL OF AN ATOM CAN ONLY HOLD 8 ELECTRONS

BOHR DIAGRAM OF CARBON

1. Find your element on the periodic table

2. Find the atomic number protons and # Electrons (e-)

Protons? Neutrons? Electrons?

Outermost electrons are called valence electrons

PRACTICE: HELIUMDraw the Bohr diagram for Helium

Protons?Neutrons?Electrons?

REMEMBER: LOW HIGH

1.1st shell holds 2 electrons

2.2nd shell 8 electrons3.3rd shell 18 electrons

Work on WS now.

WARM-UP (09/16) Draw the Bohr diagram for Silicon.

How is it similar to carbon’s diagram?

BOHR MODEL PERIODIC TABLE

What can these diagrams tell us about the groups (vertical columns) in the periodic table?All elements in the same group…

What can these diagrams tell us about the periods (horizontal rows) in the periodic table?All elements in the same period…

Why might valence electrons be important?

THE PERIODIC TABLEValence electrons allow an atom to participate in chemical reactions

Groups tell us how many valence e- there are

Periods tell us how many e- shells there are

WARM-UP (09/17)

Draw the Bohr diagram for magnesium.

Which period is it in? (Period # ______ )

Which group is it in? (Group # ______ )

POP QUIZPlease take out 1 sheet of paper and rip it in half. You will use the other half at the end of class

POP QUIZ

1. Draw the Bohr diagram for nitrogen.2. The electrons in the outermost shell

are called _______________ electrons.3. What do all elements in the same

group share? Ex. All elements in the same group…

4. What do all elements in the same period share?

HISTORY OF THE PERIODIC TABLE (1865) John Newlands – law of octaves similar properties every eight elements Order based on atomic mass

(1869) Dmitri Mendeleev first periodic table (63 known elements at the time)Some elements didn’t “fit” correctly(by atomic mass)

HISTORY OF THE PERIODIC TABLE

HISTORY OF THE PERIODIC TABLE

Henry Moseley realized the periodic table should be organized by atomic ____________, NOT atomic _____________.

This “fixed” Mendeleev’s periodic table

THE MAIN-GROUP ELEMENTS

Groups 1-2, 13-18 are known as ________________________.

Electron behavior is regular and consistent

GROUP 1 – ALKALI METALS

GROUP 1 – ALKALI METALSList some characteristics of Alkali metals.

SoftHighly reactiveReacts with air Reacts (violently) with water

EXIT SLIP (ANSWERS ONLY)

1. List two properties of Alkali Metals

2. Why do all elements in the same group share similar properties? (Think about what they have in common)

WARM-UP (09/18) Why do all elements in the

same group share similar properties? (Think about what they have in common)

[You may want to review Bohr diagrams of same-group elements]

Predict how many valence electrons are in Strontium (Sr). Explain your answer.

GROUP 1 – ALKALI METALS

GROUP 1 – ALKALI METALSList some characteristics of Alkali metals.

SoftHighly reactiveReacts with air Reacts (violently) with water

GROUP 2 - ALKALINE EARTH METALS

How many valence electrons? Very reactive (not as much as alkali metals)

Ex. Be, Mg, Ca, Sr, Ba

Please write down characteristics of halogens during the video

GROUP 17 - HALOGENS

GROUP 17 - HALOGENS

How many valence electrons? Properties?Most reactive group of nonmetal

elementReact with most metals to produce

salts

GROUP 17 - HALOGENS

GROUP 18 – NOBLE GASES

GROUP 18 – NOBLE GASES What is the main characteristic of noble gases?

They are unreactive & very stable

How do they achieve stability?

HYDROGEN IS TOO COOL

Behaves unlike any other element

Is in it’s own class!

GROUPS 3-12: TRANSITION METALS

Unlike main group elements, the electrons may vary

Ex. Copper, platinum, gold, silver, iron

EXIT SLIP

What are some properties of metals that you know of?

What seems to be the “magic number” when it comes to valence electrons? (Hint: what makes an atom stable)

HAPPY FRIDAY! NOW TURN IN YOUR WORK

You have 7 minutesDUE NOWWarm-Ups (9/15 – 9/18)

HW #11 (complete)& HW #12

WARM-UP (09/23/14) Periods, or rows, tell us how many__________ __________ are in an atom.

As you move DOWN a group, what do we notice about the number of electron shells?

GUIDED NOTES REVIEW“What is the f in the box mean?” “Why does it matter if an atom is

‘happy’” ?“What is it called when you add an

electron?” “How does an atom change when it

loses an electron?”“How can you have different

numbers of protons and electrons?”

IONIZATION ENERGY AND ELECTRON SHIELDINGWhat is ionization energy? The energy required to remove an electron from an atom or ion

Compare Lithium and Potassium

Li K

IONIZATION ENERGY AND ELECTRON SHIELDINGCompare Lithium and Potassium

Li K

Potassium (K) has more __________ between it’s valence electron and the nucleus

Electron shielding causes valence e- to be held less tightly to the nucleus

ELECTRONS ARE LIKE CONCERT-GOERS

The band is the nucleus (+) Closer you are to the band, the less

you can moveIf you’re further out, you can easily

leave the concert

The more people between you and the band, the less attracted you are to the concert

IONIZATION ENERGY TRENDS

Remember, ionization energy is the energy needed to remove an electron

Ionization energy decreases as you go down a group

Ionization energy increases as you go across a period.

Li Ne

IONIZATION ENERGY TRENDS

Think of it as 3 magnets vs. 10 magnets

More protons greater effective nuclear charge

Ionization energy increases as you go across a period

Li Ne

ATOMIC RADIUSAs you go down a group, you add

another electron shell.

Li

K

As you go down a group, the atomic radius will increase.

ATOMIC RADIUS TRENDS

3 magnets vs 10 magnetsMore protons greater effective nuclear charge

Protons “pull” the electrons closer in

Atomic radius decreases as you go across a period

Li Ne

ELECTRONEGATIVITY

Electronegativity – a measure of the ability of an atom in a chemical compound to attract electrons

Electronegativity decreases as you go down a group Electron shielding prevents protons

from attracting electronsElectronegativity increases as you go across a period

EXIT SLIP (ANSWERS ONLY)1. Write the periodic trends for

TWO properties discussed today

Ex. As you go down a group, _________ will increase/decrease and as you go across a period…

2. For you, what is the most difficult thing we have learned about in chapter 4 (Bohr/periodic table)?

WARM-UP (09/24/14)

What is ionization energy? Which group would have the lowest ionization energy?

What is electronegativity? Which group would have the highest electronegativity?

WHOLE CLASS REVIEWDraw the Bohr diagram for oxygen Groups are GUD (Go UP and

DOWN/vertical) Periods are LONG (side to side/ horizontal) All elements in the same ___________ have

the same number of valence electrons.Ex. All elements in the first group have ___

valence electron.All elements in the same ___________ have

the same number of electron shellsEx. All elements in the 3rd period have _____

e- shells

REVIEW OF YESTERDAY: GROUP TRENDS

As we go down a group, we add an electron shell.

This causes more electrons to be between our nucleus (+) and our valence electrons ( - ).

This makes it easier to remove valence electrons because more electrons SHIELD or BLOCK the positive charge coming from the nucleus

Li

Na

REVIEW OF YESTERDAY: GROUP TRENDS

If there is more electron shielding, it is easier to remove an electron (Ionization energy decreases)

But it is harder to attract electrons (Electronegativity decreases)

More shells increase in atomic radius

Li

Na

REVIEW OF YESTERDAY: GROUP TRENDS

As we go across a period, we add protonsThis causes the nucleus (+) to have a

greater positive pull on electrons (-)This makes it harder to remove valence

electrons because more protons are holding the electrons closer to the nucleus

Li Ne

REVIEW OF YESTERDAY: GROUP TRENDS

If it is harder to remove electrons, it requires more energy (Ionization energy increases)

More protons mean they can attract electrons more easily (Electronegativity increases)

More protons mean they pull electrons closer towards the nucleus (Atomic radius decreases)

Li Ne