Chapter 7 Properties Of The Elements

Front 1

Elements in the same column...

Back 1

...contain the same number of valence electrons

Front 2

Effective Nuclear Charge

Back 2

the net positive charge experienced by an electron in a many electron system / atom

Front 3

Zeff < Z because....

Back 3

Zeff takes into consideration electron-electron repulsions

Front 4

The shielding effect

Back 4

the electron density due to inner electrons that are responsible for shielding valence electrons from attraction to nucleus

Front 5

Zeff =

Back 5

....Zeff = Z -S; Z is the # of protons in the nucleus, S is a positive valued called the screen constant and is approx. equal to the number of core electrons

Front 6

Nuclear charge and distance observation...

Back 6

energy of 2p orbital ( l= 1)is slightly higher than 2s orbital (l = 0) even thought both occupy n = 2 shell

Front 7

Zeff Trend

Back 7

Zeff increases down a row. In general, Zeff increases down a group but its not a strong patter

Front 8

Apparent Radius

Back 8

the closest distance separating two atoms during a collision aka nonbonding atomic radius. This radius gives the estimate size of an atom when this atom is not involved in bonding

Front 9

Bonding Atomic Radius

Back 9

The attraction between two atoms or molecules that leads to the formation of an atomic bond

Front 10

Atomic Radii Trend

Back 10

Atomic radii increases from top to bottom. Atomic radii decreases from left to right across a row

Front 11

Factors of Trends in Atomic Radii

Back 11

1. principal quantum number (leads to an increase in radii) 2. effective nuclear charge (responsible for decrease going across a row)

Front 12

Ionic size...

Back 12

varies with the periodic table

Front 13

Cations

Back 13

smaller radii than parent atoms...remove electron furthest from nuclei....decrease in electron-electron repulsions...increase Zeff

Front 14

Anions

Back 14

larger radii relative to parent atoms...ad electron to orbital that is furthest from nucleus...increase electron-electron repulsion...decrease Zeff

Front 15

Ions with the same charge...

Back 15

the size of atomic radius increases as you go down group

Front 16

Isoelectronic series

Back 16

a series of atoms (groups of ions) with the same number of electrons

Front 17

Ionization energy

Back 17

the minimum energy that it takes to move an electron from the ground state of an isolated gaseous atom or ion

Front 18

1st Ionization energy

Back 18

the energy needed to remove the first electron from neutral atom

Front 19

2nd Ionization energy

Back 19

energy needed to remove the second electron

Front 20

The larger the ionization energy...

Back 20

the more difficult to remove electron

Front 21

As each successive electron is removed...

Back 21

there is an increase in Zeff for remaining electrons because of a reduction in electron electron repulsion therefore it is more difficult to remove second electron

Front 22

Ionization energy genereally increases with...

Back 22

increasing atomic number within a row for I1; I1 increases as Zeff increases

Front 23

Ionization energy decreases...

Back 23

down a group

Front 24

1st Ionization energy for noble gases....

Back 24

decreases

Front 25

Electron Affinity

Back 25

energy change that occurs when an electron is added to gaseous state of a neutral atom; measures affinity of the atom for an electron

Front 26

Ionization Energy vs. Electron Affinity

Back 26

Ionization --> how easily an atom loses and electron ; electron affinity --> how easily an atom gains an electron

Front 27

Metallic character trend...

Back 27

increases as you go down a group increases as you go to left to right; know 7.3 Table

Front 28

Metals characteristics...

Back 28

low ionization energies, tend to form positive ions very easily

Front 29

Metal Oxides

Back 29

most metals are basic...Sodium Hydroxide NaOH

Front 30

Nonmetals

Back 30

have a tendency to gain electrons because of their electron affinity, most nonmetal oxides are acidic

Front 31

Metalloids

Back 31

have properties of both metals and non metals

Front 32

Alkali Metals

Back 32

1A, soft, metallic solids, low density, low melting points, reactivity increases as you go down a group because 1st ionization energy decreases

Front 33

Halides

Back 33

when alkali metals reach with hydrogen

Front 34

Alkaline Earth Metals

Back 34

higher melting points, smaller atomic radii, reactivity increases as you go down a group

Front 35

Hydrogen

Back 35

does not really belong to any group, nonmetal, colorless, diatomic gas under most conditions, under tremendous pressure it will behave like metal

Front 36

Oxygen Group

Back 36

as you go down the group the metallic characteristics of the elements increase, when oxygen combines with metals it forms O2- ion

Front 37

Halogens

Back 37

as a group have a highly negative electron affinity

Front 38

Fluorine

Back 38

the most reactive element, reacts with almost every substance it comes in contact with

Front 39

The Noble Gases

Back 39

nonmetal gases at room temperature, completely filled s and p orbitals, highest ionization energy, highly un reactive