Ionization Energy
What are the three periodic trends we learned about?
Atomic Radius, Ionization Energy, and Electronegativity
What is atomic radius?
It is half the distance between two adjacent nuclei of atoms of the same element.
What does electronegativity tell us about?
Electronegativity tells us how strongly an atom holds onto/attracts electrons to itself.
Which is a good conductor of electricity and shiny (metal, metalloid, or nonmetal)?
Metal.
Name for elements in Group 1 on periodic table.
Alkali metals
How many valence electrons are in calcium?
2
What is ionization energy?
The energy required to remove a valence electron.
What is the periodic trend in atomic radius?
Increases from top to bottom within a group, decreases from left to right within a period.
What is the periodic trend in electronegativity?
It decreases from top to bottom within a group, and it increases from left to right within a period.
What are the general characteristics of metalloids?
Share properties of both metals and nonmetals
Name for elements in group 2 on the periodic table.
Alkaline Earth metals
How many valence electrons are in bromine?
7
Describe the periodic trend of Ionization energy across a period and down a group
Decreases from top to bottom within a group, increases from left to right within a period.
How many energy levels does gallium have?
4
Order the following elements in increasing electronegativity:
C, Si, Ge, Sn, and Pb.
Pb<Sn<Ge<Si<C
Poor conductors of electricity and not shiny, not malleable, not ductile.
Nonmetals.
What is the name for the group of elements in Group18 of the Periodic Table?
Noble Gases.
Unreactive
How many valence electrons are in Helium?
If it's easy to remove an electron, is ionization energy low, or high?
Low
How many energy levels does cerium have?
6
Use what you know about periodic trends to determine which of the following is ordered correctly from least to most electronegative.
a) F, N, B, Li
b) Li, Na, K, Rb
c) Al, Si, P, S
d) Be, Mg, Ca, Sr
Give an example of a metalloid
Boron, silicon, germanium, arsenic, antimony, tellurium, polonium
These elements are extremely toxic and have 7 valence electrons.
Halogens.
Why is potassium more likely to lose an electron and become positive, than to gain an electron?
When it loses an electron it ends up with a full valence shell and is more stable.
Explain why we observe the periodic trends in ionization energy across a period and down a group.
It decreases from top to bottom within a group because energy levels are added, which increases the distance between the valence electrons and the nuclear pull. There are also more core electrons to shield the pull from the nucleus, which makes it easier to remove electrons, making ionization energy decrease.
It increases across a period, because nuclear charge increases without adding energy levels, so that increases the attraction for electrons and makes them harder to remove, which increases ionization energy.
Explain why we observe the periodic trends in atomic radius across a period and down a group.
It increases from top to bottom within a group because energy levels are added, which increases the distance between the valence electrons and the nucleus.
It decreases across a period, because nuclear charge increases without adding energy levels, so that increases the attraction for electrons which pulls them in and makes the atom smaller.
Explain why we observe the periodic trends in electronegativity across a period and down a group.
It decreases from top to bottom within a group because energy levels are added, which increases the distance between the valence electrons and the nuclear pull. There are also more core electrons to shield the pull from the nucleus, which reduces its ability to attract electrons, making electronegativity decrease.
It increases across a period, because nuclear charge increases without adding energy levels, so that increases the attraction for electrons, thus increasing electronegativity.
What's the difference between a group and a period? What information can we get from them ?
Groups are the vertical columns on the periodic table, periods are the horizontal rows.
Groups tell us the number of valence electrons, periods tell us how many energy levels are used to arrange the electrons.
Why are noble gases chemically stable?
They have an octet. (full valence shell)
What is a noble gas that is stable but doesn't have an octet (8 valence electrons)?
Helium (only needs 2 to fill valence shell)