Chapter 6Chapter 6

The Periodic TableThe Periodic Table

Anything in black letters = write it in your notes (‘knowts’)

UNIT 3 – Periodic Table & Bonding UNIT 3 – Periodic Table & Bonding Chapter 6 – The Periodic Table Chapter 6 – The Periodic Table

Chapter 7 – Ionic BondingChapter 7 – Ionic Bonding Chapter 8 Chapter 8 – Covalent Bonding– Covalent Bonding

Objectives for Chapter 6

1. Describe ways in which the modern periodic table is organized

2. Understand electron configuration patterns in the periodic table

3. Describe and explain trends in the periodic table

6.1 – Organizing the Elements6.1 – Organizing the Elements

Dmitri Mendeleev (1869) – created 1st modern periodic table; arranged elements based on atomic mass and chemical properties.

Mendeleev arranged elements with similar properties in the same row.

He also left gaps where proposed elements should be.

These gaps were later filled in as more elements were discovered.

Ga & Ge Discovered later

Similar properties

Mendeleev’s table was an accepted success because it predicted the properties of elements that had not yet been discovered.

Woo Hoo!

Today’s periodic table is arranged in order of increasing atomic number (not mass).

Also, elements with similar chemical properties are placed in the same vertical column.

Valence Electrons – Electrons in the highest occupied energy level; maximum of 8.

Elements in the same column have similar properties because they have the same number of valence electrons.

Cha

pter

7

Electron configurations for Group 1

(valence e- underlined)1s1

1s22s1

1s22s22p63s1

1s22s22p63s23p64s1

1s22s22p63s23p64s23d104p65s1

[Xe]6s1

[Rn]7s1

1s22s22p5

1s22s22p53s23p5

Get the idea?...

Why is it called the Periodic Table of the Elements?

The properties of the elements repeat going across each row.

Three broad classes of elements; metals, metalloids, nonmetals

Metals – good conductors of heat and electricity, shiny, most are solid at room temp (except Hg), malleable, ductile

Nonmetals – not metals!, most are gases at room temp

Metalloids – can show properties of both metals and nonmetals

6.2 – Classifying the Elements6.2 – Classifying the Elements

Columns are called groups or families.

Horizontal rows are called periods.

Chapter 6 Practice1.Explain why Mendeleev’s table was an accepted success.

2.Why is the table of elements called the “periodic” table of elements?

3.How is the modern periodic table arranged?

4.State 4 properties of metals.

5.What is the explanation for the reason elements in the same column have similar chemical properties?

6.How can you tell if an elements is a metal, nonmetal or metalloid from the periodic table?

7. Name an element that is part of the

a) Halogen family

b) Alkali metal family

c) Alkaline earth metal family

d) Transition metals

e) Inner transition metals

f) Noble gas family

8. A horizontal row in the periodic table is called a _____.

9. Write the electron configuration for

a) Nitrogen

9. Write the electron configuration for

a) Nitrogen

b) Chlorine

c) Rubidium

10. How many valence electrons are in each element from question 1?

Chapter 6 ASSIGNMENT (p. 166-173)

#1-17

Atomic size

Ionic size

Ionization Energy

Electronegativity

6.3 – Periodic Trends6.3 – Periodic Trends

Atomic SizeA

tom

ic r

adiu

s (p

m)

Atomic number

Atomic size generally decreases from left to right across a period.

As Z increases across a row, the +/- electrical attraction increases, making the atom smaller.

As Z increases down a group, more energy levels are in the atom which ‘shield’ the outer electrons from this nuclear attraction.

Ion – atom or group of atoms that has a positive or negative charge.

Ions are formed when electrons are transferred between atoms.

Cation – ion with a positive charge.

Anion – ion with a negative charge.

Metals tend to form + ions (cations)

Nonmetals tend to form - ions (anions)

Atom Ion

Li Li+

Na Na+

K K+

Rb Rb+

Atom Ion

Be Be2+

Ca Ca2+

Sr Sr2+

Ba Ba2+

Atom Ion

O O2-

S S2-

Se Se2-

Te Te2-

Ionic Size

Cations are smaller than the atoms they formed from

Anions are larger than the atoms they formed from.

Ionic Size

Ionization Energy – energy required to remove an electron from an atom.

Ionization Energies of Some Common Elements

Symbol First Second Third

H 1312

He (noble gas) 2372 5247

Li 520 7297 11,810

Be 899 1757 14,840

C 1086 2352 4619

O 1314 3391 5301

F 1681 3375 6045

Ne (noble gas) 2080 3963 6276

Na 496 4565 6912

Mg 738 1450 7732

S 999 2260 3380

Ar (noble gas 1520 2665 3947

K 419 3096 4600

Ca 590 1146 4941

Fir

st io

niz

atio

n e

ner

gy

(kJ/

mo

l)

Atomic number

Electronegativity – tendency of an atom to attract electrons of another atom.

Metals have low e-neg values,

Nonmetals have high e-neg values

B<H<C

Noble gases do not have e-neg values

Electronegativity Values for Selected Elements

H 2.1

Li 1.0

Be1.5

B2.0

C2.5

N3.0

O3.5

F4.0

Na 0.9

Mg1.2

Al1.5

Si1.8

P2.1

S2.5

Cl3.0

K 0.8

Ca1.0

Ga1.6

Ge1.8

As2.0

Se2.4

Br2.8

Rb 0.8

Sr1.0

In1.7

Sn1.8

Sb1.9

Te2.1

I2.5

Cs 0.7

Ba0.9

Tl1.8

Pb1.9

Bi1.9

Chapter 6 ASSIGNMENT (p. 182)

#18-25

Chapter 6 ASSIGNMENT (p. 188)

#26, 27, 30, 34,

39-42, 45-47, 49-51, 53, 62, 64, 75

A little more for Chapter 6…

Energy levels can also be called electron shells

Each shell corresponds to a period on the table.

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Electrons in the s and p orbitals of the outer shell are the valence electrons.

8 is the maximum number of valence electrons

The noble gases are chemically stable because they have a full outer shell (valence).

Atoms tend to gain or lose electrons to have a full shell

Sodium: 1s22s22p63s1

Magnesium: 1s22s22p63s2

Fluorine: 1s22s22p5

Nitrogen: 1s22s22p3

Chapter 6 Quiz ReviewTerms to know:

valence electron,

cation,

anion,

electronegativity,

ionization energy (1st & 2nd)

Things to know:

Metal, nonmetals, metalloids locations

4 properties of metals

metals form cations, nonmetals form anions

family names (alkali, alkaline earth, noble, halogens, transition and inner transition)

electronegativity and ionization energy trends

electron configurations (w/out aufbau diagram)

Possible Short Answer Questions:

1. Why was Mendeleev’s table an accepted success?

2. Why is the periodic table called the “periodic” table?

3. What causes elements in the same column to have similar chemical properties?

4. What is an ion and how are ions formed?

5. Why is the 2nd ionization energy of Na so much larger than the 1st ionization energy?