The Periodic Table
Dmitri Mendeleev arranged the elements according to atomic mass and used the arrangements to predict the properties of missing elements.

The Periodic Table

The modern periodic table is arranged in order of increasing atomic number.

The atomic number is the total number of protons in the nucleus.

The electron mostly determines the properties of an element.

The Periodic Table

Indium:

______ protons
______ electrons

49 49

The Periodic Table

GROUPS vertical columns

Old 1A - 8A new 1 - 18


Periods - horizontal rows

Magnesium is in the same group as calcium.

Magnesium is in the same period as phosphorus.

The Periodic Table

Metals include the majority of the elements.
Pt is a metal.
Si is a metalloid.
Kr is a nonmetal.

Metals are shiny, malleable (hammered into sheets), ductile (drawn into wires), solid at room temperature, and good conductors of electricity.

The Periodic Table

Nonmetals are poor conductors of electricity, often gases at room temperature, and brittle if solid.

Metalloids have some properties of metals and nonmetals.

Group 8A - noble gases

Group B - transition metals

The Periodic Table

Aluminum is a representative element.

Copper is a transition metal.

Na is an _______________________

Mg is an _______________________

F is a ________________________

Ne is a ______________________

Ag is a ______________________

The Periodic Table

Na is an alkali metal

Mg is an alkaline earth metal

F is a halogen

Ne is a noble gas

Ag is a transition metal

The Periodic Table

There are 5 electrons in the valence level of an element in Group 5A.

N, P, As, and Sb have the same number of electrons in their valence levels.

The Periodic Table

The electron configuration for an element in the halogen group should always end with ns 2 np 5 .

The electron configuration of the element chlorine ends in 3s 2 3p 5 .

The Periodic Table

Noble gases (inert gases) have their highest occupied s and p sublevels filled.

Fe contains an electron in a d sublevel.

Atomic size

The atomic radius increases from top to bottom in a group in the periodic table.

As you move down a group in the periodic table, atomic size generally increases

Atomic size

The atomic radius decreases from left to right across a period in the periodic table.

Lithium has the largest atomic radius in the second period.

As the number of electrons added to the same energy level increases, atomic size generally decreases.

Atomic size

List the symbols for sodium, sulfur, and cesium in order of increasing atomic radii _____________________ The largest atom in Group 1A is
______________

The smallest atom in Group 7A is
______________

Atomic size

List the symbols for sodium, sulfur, and cesium in order of increasing atomic radii: S, Na, Cs

The largest atom in Group 1A is Fr.

The smallest atom in Group 7A is F.

Ions & Ionization

Ions form when electrons enter or leave atoms.

Ions & Ionization

The charge of a cation is positive.
Cations are smaller than the original atom.

An anion has a negative charge. Anions are larger than the original atom.

Ions & Ionization

Removing one electron from an atom results in the formation of an ion with a
1+ charge.

Ions & Ionization

Ionization energy - energy required to move an electron out of an atom

Ionization energy decreases from top to bottom and increases from left to right on the periodic table.

Ions & Ionization

Among Na, K, and Cs, which element has the lowest ionization energy?

Which is larger, K or K+?

Which is smaller, Li, Li+, F, or F- ?

Ions & Ionization

Among Na, K, and Cs, which element has the lowest ionization energy?
Cs

Which is larger, K or K+?
K

Which is smaller, Li, Li+, F, or F- ?
Li +

Electronegativity

Electronegativity is the ability of an atom in a compound to attract electrons

Electronegativity

Electronegativity values tend to decrease from top to bottom and increase from left to right.

Electronegativity

Which element in each pair has a higher electronegativity value?

Mg, Ne

Cl, F

C, N

As, Ca

Electronegativity

Which element in each pair has a higher electronegativity value?

Mg, Ne Mg

Cl, F F

C, N N

As, C As

Electronegativity

Cs has one of the lowest electronegativity values.

Electronegativity

Valence (outer) electrons may be transferred from one atom to another.


Group Valence electrons

1A

2A

3A
Lose 1
Lose 2
Lose 3
Resulting charge
1 +
2 +
3 +

-
-
-

Electronegativity
What charge would Na likely have in a compound? _______
What charge would Mg likely have in a compound? _______
What charge would Al likely have in a compound? _______

Electronegativity
 What charge would Na likely have in a compound? 1+
 What charge would Mg likely have in a compound? 2+
 What charge would Al likely have in a compound? 3+

Electronegativity

What charge would O likely have in a compound? _______

What charge would F likely have in a compound? _______

Electronegativity

What charge would O likely have in a compound? 2-

What charge would F likely have in a compound? 1-