Ch 5 Section 2 Flashcards
Stability o noble gases results from
The gases special electron configurations
Generally the electron configurations of an atoms highest occupied energy level governs
The atoms chemical properties
Elements are arranged vertically in periodic table in groups that share
Similar chemical properties
Periods
Horizontal rows
7 in the modern periodic table
Length of each period is determined by the number of
Electrons that can occupy the sublevels being filled in that period
The 1s sublevel is being filled in the
First period
1s sublevel can hold a total of
2 electrons, and thus, it consists of two elements
In the second period the following sublevels are being filled
2s
2p
2s sublevel can hold
2 electrons
2p sublevel can hold
6 electrons
Second period totals
8 elements
Filling of the 3s and 3p sublevels accounts for
The eight elements of the third period
Filling 3d and 4d sublevels in addition to s and p sublevels adds
10 elements to both the fourth and fifth periods
Thus each of these periods totals 18 electrons
Filling 4f sublevels in addition to s p and d sublevels adds
14 elements to 6th period which totals 32 elements
As new elements are created the 25 named elements in period 7 could be
Extended to 32
Period of an element can be determined from the
Elements electron configuration
Coefficient in highest energy level= period
Periodic table is divided into
4 blocks S P D F
Elements of the s block are chemically
Reactive metals
Group 1 metals are more reactive than
Those of group 2
The ease with which the single electron is lost helps to make the group 1 metals
Extremely reactive
The elements of group 1 of the periodic table
(Lithium, sodium, potassium, rubidium, cesium, francium) known as the alkali metals
In pure state all alkali metals have a
Silvery appearance and are soft enough to cut with a knife
Alkali metals are not found in
Nature as free elements
Alkali metals combine
Vigorously with most nobmetals and react strongly with water to produce hydrogen gas and aqueous solutions of substances known as alkalis
Alkali metals are usually stored in
Kerosene
Preceding down the volume the elements of group 1 melt at
Successively lower temperatures
The elements of group 2 of the periodic table
(Beryllium, magnesium, calcium, strontium, barium, radium) are called the alkaline earth metals
Atoms of alkaline-earth metals contain a
Pair of electrons in their outermost s sublevel
Group configuration for group 2 is
ns^2
Group configuration of group 1 is
ns^1
Group 2 metals are (comparison with alkali metals)
Harder
Denser
Stronger
Higher melting pts than alkali metals
Alkaline earth metals are also too
Reactive to be found in nature as free elements
Hydrogen does not share the
Same properties as elements of group 1
Unique element
Helium has ns^2 configuration like group 2 but is part of
Group 18
Because its highest occupied energy level is filled by two electrons helium possessed
Special chemical stability exhibiting the unreactive nature of a group 18 element
Group 2 metals have no
Special stability
Highest occupied energy levels aren’t filled because each metal has an empty p sublevel
For energy level n there are
N possible sublevels
In addition to the two ns electrons of group 2 Atoms of the group 3 elements each have
One electron in the d sublevel of the (n-1) sublevel
Group configuration for group 3 is
(n-1)d^1ns^2
Atoms of the group 12 elements have
10 electrons in the d sublevel plus two electrons in the ns sublevel
Group configuration for group 12 is
(n-1)d^10ns^2
The d block elements are metals with
Typical metallic properties and are often referred to as transition elements
D block elements are
Good conductors of electricity and have a high luster
Typically Less reactive than alkali metals and alkaline earth metals
Some d block elements are so unreactive that they do not
Easily form compounds, existing in nature as free elements
Atoms of all p block elements contain
2 electrons in the ns sublevel
The p block elements together with the s block elements are called the
Main group elements
For group 13 elements added electron enters the
Np sublevel giving group configuration of ns^2np^1
Atoms of group 14 elements contain 2 electrons in p sublevel giving
ns^2np^2 for group configuration
Group configuration for 13-18
ns^2np^1-6
For atoms of p block elements the total number of electrons in the highest occupied level is equal to
The group number minus 10
At right hand end p block includes all of the
Nobmetals except hydrogen and helium
All six of the metallloids are also in the
P block
At the left hand side and bottom of the p block there are
Eight p block metals
The elements of group 17
(Fluorine, chlorine, bromine, iodine, astatine)
Are known as halogens
Halogens are the most reactive
Nonmetals
The reactivity of halogens is based on the presence of
7 electrons in their outer energy levels- one electron short of the stable noble gas configuration
Fluorine and chlorine are
Gases at room temp
Bromine is a
Reddish liquid
Iodine is a
Dark purple solid
Astatine is a synt
Synthetic element prepared in only very small quantities
Metallloids are located between
Nonmetals and metals in p block
Metals of the o block are generally
Harder and denser than the s block alkaline earth metals but softer and less dense than the d block metals
With exception of bismuth the metals of p block are sufficiently
Reactive to be found in nature only in form of compounds
The position of f block elements reflects the fact that
They involve the filling of the 4f sublevel
Lanthanides are shiny
Metals similar in reactivity to alkaline earth metals
Actinides are all
Radioactive
First four found naturally and remaining are lab made
Group 18 elements of the periodic table undergo
Few chemical reactions
