Chapter 5 Chemistry
Periodic Law
the physical and chemical properties of the elements are periodic functions of their atomic numbers.
How many valence electrons does Group 13 have?
3
How many valence electrons does Group 14 have?
4
How many valence electrons does Group 15 have?
5
What is the name of Group 17?
Halogens
What is the trend for electron affinity as you move across a period from left to right?
Increases, except for when it hits the noble gases.
What happens to atomic radii as you move down a period? What causes this trend?
It becomes larger. The cause of this trend is it is adding more energy levels.
What happens to the atomic radii going from left to right across a period? What causes this trend?
It becomes smaller. The cause of this trend is it is adding more protons, pulling them together.
What is the name of Groups 13-16?
Main groups
Which ion is larger and why Al^3+ or Mg^2+?
Mg^2+ because atom only has 2 electrons
Who gave us the modern periodic chart?
Moseley
What do metals tend to form?
cations
Explain why atomic radii increases going from right to left, top to bottom, and decreases when going left to right, and bottom to top.
it is losing protons
Explain why ionization energy is decreasing when going from right to left, top to bottom, and increasing when going left to right, and bottom to top.
its closer to the nucleus
What elements make up the f-block in the periodic table?
lanthanides and actinides
Alkaline-Earth Metals
one of the elements of Group 2 of the periodic table.(Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.)
Atomic Radius(radii)
one-half the distance between the nuclei of identical atoms that are bonded together.
Where are Valence Electrons found?
outermost energy level
Where are the metalloids found on the periodic table?
p-block
Where are nonmetals found on the periodic table?
p-block only
Determine which of the following electron configurations represents an element with lower reactivity compared to the other element. Record the period and group of that element in the grid, putting period number first, followed by a space, followed by the group number. 1s2 2s2 2p6 3s2 3p2 1s2 2s2 2p6
period 3, group 14, Si period 2, group 18
How many valence electrons does Group 1 have?
1
How many valence electrons does Group 2 have?
2
Without looking at the periodic table, identify the period, block, and group in which the elements with the following electron configurations are located. a. [Ne]3s^2 3p^4 B. [Kr]4d^10 5s^2 5p^2
A. Period 3, p-block, Group 6 B. Period 5, d-block, Group 14
Moseley
Arranged the periodic table according to *atomic number* instead of mass.
The two ions K+ and Ca2+ each have 18 electrons surrounding the nucleus. Which would you expect to have the smaller radius? Why?
Ca2+ because it has more protons than electrons.
Mendeleev
Created the first periodic table. Arranged elements by increasing *atomic mass*.
What element is most electronegative?
Fluorine
What is the name of Group 18?
Nobel gases
What element is the second highest?
Oxygen
Which element is the most electronegative among C N, O, Br, and S? Which group does it belong to?
Oxygen, Group 16
What trend can be observed as you move across the period of Ionization Energy?
R to L decreases ; L to R increases. (gonna get harder to pull electrons off)
The alkaline earth metals are found in Group 2 of the periodic table. Which alkaline earth metal has the highest ionic radius based on its location on the periodic table?
Radium(Ra)
Why do the alkali metals occupy Group 1 of the modern periodic table?
The alkali metals have one valence electron in their outer shells.
Anion
a negative ion
What is the general trend for electron affinity as you move down a group?
decreases
How do valence electrons play a part in the formation of compounds?
they are available to be lost, gained, or shared to make a bond with a compound.
Where are lanthanides and actinides located on the periodic table?
they are set off *below* the main portion of the periodic table to save space.
What is the name of Groups 3-12?
transition metals
Why does the atomic radius get smaller as you move across a period but gets larger as you move down a group?
when you move across a period and it gets smaller it's because you are adding more protons, pulling them together. When it becomes larger as you move down a group it's because it's adding more energy levels.
Which of the following best describes how ionic radius changes across the periodic table?
It increases as you move down a group
What trend can be observed as you move across the period of atomic radii?
L to R decreases ; R to L increases. (caused by the increase in the number of protons and electrons across a period.)
Of cesium, Cs, hafnium, Hf, and gold, Au, which element has the smallest atomic radius? Explain your answer in terms of trends in the periodic table.
Au, decreases left to right
Which of the following elements has the smallest atomic radius? A. [Ar] 4s2 B. [Ar] 3d10 4s2 C. [Ne] 3s1 D. [Ar] 4s1
C
Actinides
the 14 elements with atomic numbers from 90(Thorium, Th) to 103(Lawrencium, Lr)
Transition Elements
the d-block elements are metals with typical metallic properties.
Valence Electrons
the electrons available to be lost, gained, or shared in the formation of chemical compounds.
Alkali Metals
the elements of Group 1 of the periodic table. (Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium.)
How many valence electrons does Group 16 have?
6
How many valence electrons does Group 17 have?
7
How many valence electrons does Group 18 have?
8
What trend can be observed as you move down a group for atomic radii?
B to T decreases ; T to B increases
What trend can be observed as you move down a group for Ionization energy?
B to T increases ; T to B decreases
What trend can be observed as you move down a group for electronegativity?
B to T increases ; T to B decreases
How is an anion formed?
By gaining electrons
Cannizzaro
Developed a standard method for measuring atomic masses. (consistently relative mass)
Explain electron affinities periodic table trend
Group 17 loses the most potential energy when it gains an electron.
How is a cation formed?
It's formed when a metal loses electrons, and a nonmetal gains those.
What are the group numbers of the 4 blocks?
S: 1-2 P: 13-18 D: 3-12 F: lanthanides and actinides..they have no group #'s
The Octet Rule
States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons. Exceptions to this rule include the elements hydrogen through Beryllium.
What do atoms prefer?
To have 2 electrons in their valence shell
What name is used to refer to the entire set of d-block elements?
Transition metals
Write the noble-gas notation for the electron configuration of Br, and indicate the period in which it belongs.
[Ar] 4s^2 3d^10 4p^5 ; period 4
Write the noble-gas notation for the electron configuration of Li, and indicate the period in which it belongs.
[He]2s^1 ; period 2
Write the noble-gas notation for the electron configuration of O, and indicate the period in which it belongs.
[He]2s^2 2p^4 ; period 2
Write the noble-gas notation for the electron configuration of Sn, and indicate the period in which it belongs.
[Kr] 5s^2 4d^10 5p^2 ; period 5
Electronegativity
a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound.
Cation
a positive ion
What is the name of Group 1?
alkali metals
What is the name of Group 2?
alkaline-earth metals
Periodic Table
an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group.
Ion
an atom or group of bonded atoms that has a positive or negative charge. (charged atom)
What do nonmetals tend to form?
anions
Ionization
any process that results in the formation of an ion.
Why are the noble gases relatively unreactive?
because their outer shells are completely filled. (s and p orbitals)
How do the electron configurations within the same group of elements compare?
by the outermost shell of electrons.
How is the periodic Law demonstrated within the groups of the periodic table?
by valence electrons and chemical properties staying the same in a group.
As you move left to right across Period 3 from Sc to Zn, the energy needed to remove an electron from an atom —
generally decreases
Where are metals found on the periodic table?
in the d-block and s-blocks. (left side)
Group 17 elements are the most reactive of the nonmetal elements because they what?
require only one electron to fill their outer energy level
Name the 4 blocks that the periodic table is divided into
s, p, d, f.
What is the relationship between the electron configuration of an element and the period in which that element appears in the periodic table?
shows the outermost energy level
Lanthanides
the 14 elements with atomic numbers from 58(cerium, Ce) to 71(Lutetium, Lu)
Halogens
the elements of Group 17.(Fluorine, Chlorine, Bromine, Iodine, and Astatine)
Electron Affinity
the energy change that occurs when an electron is acquired by a neutral atom.
Ionization Energy
the energy required to remove one electron from a neutral atom of an element.
Main-group elements
the p-block elements together with the s-block elements.
