Download II. Ch. 5.2: Electron Configuration and the Periodic Table

Unit 5 Guided Notes
I.
Ch. 5.1: History of the Periodic Table
A.
Warm Up
1.
Using the periodic table, determine the number of protons and electrons in a chlorine atom.
2.
Identify which group and period chlorine is located on the periodic table.
3.
Is chlorine considered a metal, nonmetal, or metalloid?
a)
4.
Explain your choice.
What is the mass of one mole of chlorine atoms?
5.
Name two other elements that would have similar chemical properties as chlorine. Explain your
choices.
B.
History of the Periodic Table
1.
Russian chemist Dmitri Mendeleev (1869) wanted to organize known elements by properties.
2.
When he arranged elements by increasing ______________ ________________, he noticed that similar
elements occurred at regular intervals.
C.
Mendeleev’s Periodic Table
1.
He called his chart the “________________” table.
2.
In order for similar elements to line up, Mendeleev left gaps in his chart.
3.
Mendeleev stated these were undiscovered elements. He made ________________________ about
these undiscovered elements based on the other elements in the same row.
a)
By 1886, these elements (scandium, gallium, and germanium) were discovered and their
properties closely matched his predictions.
D.
Mendeleev has Unresolved Issues
1.
With the discovery of Mendeleev’s predicted elements, most chemists were persuaded to accept his
table. However, there were two issues unresolved by his table.
a)
What caused elements to have similar properties?
b)
Why were there certain cases when a heavier element had to be placed in front of a light
element so properties would line up (Te and I)?
E.
Moseley and the Periodic Table
1.
Henry Moseley (1911) – discovered technique to determine nuclear charge of atom.
a)
2.
He called this the ________________ __________________.
Every element had its own unique atomic number.
3.
When Moseley arranged elements by increasing atomic number, the inconsistencies of Mendeleev’s
table disappeared.
F.
Modern Periodic Table
1.
Periodic Law – when elements are arranged by increasing ______________ __________________,
elements with similar chemical and physical properties occur at regular intervals.
2.
Today the periodic table arranges elements by ________________ and _____________________.
a)
Group – vertical column of elements
(1)
b)
G.
also known as families
Period – horizontal row of elements
Changes in the Periodic Table
1.
There have been significant changes to the periodic table since Mendeleev created his chart.
a)
Noble Gases – elements that make up group 18. Include He, Ne, Ar, Kr, Xe, and Rn.
(1)
Extremely unreactive gases
(1)
Very stable elements that __________ ____________ combine with other atoms in
nature.
b)
c)
H.
Reflection
Lanthanide series – elements 58-71
(1)
Also called rare earth elements since they are hard to identify and separate.
(2)
These elements are part of period 6.
Actinide series – elements 90-103
(1)
Most are ___________________ and all are radioactive.
(2)
These elements are part of period 7.
II.
Ch. 5.2: Electron Configuration and the Periodic Table
A.
B.
Warm Up
1.
Write the electron configurations for magnesium and calcium.
2.
What do these configurations have in common?
3.
Where are these two elements located on the periodic table?
4.
Without writing the entire configuration, predict how the electron configuration of barium ends.
Electron Configurations and the Periodic Table
1.
The periodic table is arranged by how the electrons within an atom fill orbitals.
2.
ends.
The periodic table is broken into ___________ according to how the electron configuration of an atom
3.
s-block
a)
Configurations end in s1 or s2
b)
Composed of groups 1 and 2
(1)
c)
4.
Group 1 called _____________ metals (except H)
Group 2 known as _____________ _____________ metals
P-block
a)
Configurations end in p1 – p6
b)
Compose elements that make up groups 13-18 (except He)
c)
Group 17 also called ______________ (most reactive nonmetals)
d)
Group 18 also known as _______________ ________________
5.
The s-block and p-block together are known as the main group elements.
6.
d-block
a)
Elements whose configurations end in d 1 – d10
b)
d-block elements also known as ____________________ elements.
c)
Metals in the d-block tend to have higher melting points, are harder, denser, and less reactive
compared to the metals found in the s-block.
7.
f-block
a)
Elements whose configurations end in f1 – f14.
b)
Composed of elements that make up _______________________ and ____________________
series.
C.
D.
When writing electron configurations using the periodic table,
1.
the number in front of the s is the period number
2.
the number in front of the p is the period number
3.
the number in front of the d is one less than the period number
4.
the number in front of the f is two less than the period number
Sample Problems
1.
E.
Using the period table, write the electron configuration for these atoms:
a)
phosphorus (P)
b)
tin (Sn)
Noble Gas Electron Configurations
1.
Sometimes we are only interested with electrons in the highest energy level (___________________
_________________________).
2.
In noble gas configurations, we start with the noble gas before the element and build from there.
a)
Bromine (Br)
(1)
F.
Sample Problems
1.
G.
[Ar] 4s2 3 d10 4p5
Write noble gas electron configurations for these atoms:
a)
aluminum (Al)
b)
barium (Ba)
Using Shorthand Configurations
1.
Give the identity, the block, period, and group for the atom that has the following shorthand
configuration
[Ar] 4s2 3d10 4p3
Identity: _________ Period:_________
Block: ___________ Group:_________
III.
Ch. 5.3: Periodic Trends
A.
Warm Up
1.
Using the periodic table, provide the shorthand (noble gas) configurations for magnesium and
strontium.
2.
B.
C.
Which atom would have a larger size? Explain your selection.
Periodic Trends
1.
table.
Certain patterns or ________________ concerning properties of atoms can be noticed in the periodic
2.
These include melting point, density, hardness, and reactivity.
3.
Three other trends include:
a)
Atom size
b)
Ionization energy
c)
Electronegativity
Atom Size and Atomic Radii
1.
Atom size usually represented by atomic radii.
2.
Atomic radius may be defined as one-half the distance between the nuclei of identical atoms that are
bonded together.
D.
Atomic Radii Trends
1.
As you go down a _______________, atomic radii generally ____________________.
a)
The trend to larger atoms down a group is caused by the increasing number of energy levels
within the atom.
2.
As you go across a ________________, atomic radii usually ___________________.
a)
The trend to smaller atoms across a period is caused by the increasing positive charge of the
nucleus, which attracts electrons toward the nucleus.
3.
What Do You Think?
a)
Of the elements magnesium, Mg, chlorine, Cl, sodium, Na, and phosphorus, P, which has the
largest atomic radius (circle it)?
E.
Ionization Energy
1.
Adding energy to an atom causes the atom to enter an excited state and the electron “jumps” to a
higher energy orbital.
2.
If enough energy is added, the electron can actually be removed from the atom.
3.
In this case, the atom takes on a charge and is called an ____________.
a)
A + energy  A+ + e-
4.
The energy required to remove an electron from a neutral atom of an element is the
____________________ ___________________, IE.
F.
Ionization Energy Trends
1.
Among the main-group elements, ionization energies ________________ ___________________ down
the groups.
a)
Electrons removed from atoms of each succeeding element in a group are in higher energy
levels, farther from the nucleus. (Electrons held less tightly – shielding effect)
2.
In general, ionization energies of the main-group elements _________________across each period.
a)
This increase is caused by increasing nuclear charge. A higher charge more strongly attracts
electrons in the same energy level.
G.
Its Your Turn!
1.
H.
I.
Arrange the elements oxygen, fluorine, and sulfur according to increasing ionization energy.
Electronegativity
1.
Electronegativity – measures the ability of an atom to attract electrons from another atom.
2.
Scale in which atom is assigned a number between 0 and 4.
3.
Higher the number, the stronger the attraction for electrons.
4.
Atom with highest electronegativity is ___________________. Fluorine’s value is 4.
Electronegativity Trends
1.
Metals tend to have _________ electronegativities; while nonmetals tend to have __________
electronegativities.
J.
2.
Electronegativities ________________ as you go down a group.
3.
gases.
Electronegativities generally ___________________as you go across a period until you reach the noble
Reflection