Download presentation
1
Periodic Trends: All Arrows point to increases
Electronegativity, Ionization Energy, Electron Affinity Atomic Radius, Ionic Radius, Metallic Character Melting & Boiling Point Reactivity
2
Follow along in your text Chapter 4 Sections 1 & 2 Pages 116 - 131
Periodic Table Follow along in your text Chapter 4 Sections 1 & 2 Pages
3
Newlands John Newlands (1865, English)
Organized elements by increasing atomic mass. Elements with similar properties were grouped together. Created Law of Octaves. Every 8 elements, there is a similarity.
4
Mendeleev Dmitri Mendeleev (1869, Russian)
Used Newlands’ Law of Octaves to create the first Periodic Table. There were some discrepancies.
5
Mendeleev Predicted properties of undiscovered elements.
6
Moseley Henry Mosely (1913, British)
Organized elements by increasing atomic number. Resolved discrepancies in Mendeleev’s arrangement.
7
Periodic Blocks Main Group Elements (s &p) Transition Metals (d)
Inner Transition Metals (f)
8
Blocks of the Periodic Table
9
Periodic Law When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals.
10
Let’s Get Organized! Vertical columns are called “groups” or families Same group = same number of valence electrons
11
Let’s Get Organized!(cont.)
Horizontal rows are called “periods” Elements in each row have the same amount of principal energy levels occupied
12
4 groups have special names
Main-Group Elements Are in s & p blocks Silicon & oxygen account for 4 of every 5 atoms found on or near Earth’s surface 4 groups have special names
13
Group 1: Alkali Metals React with water to make alkaline solutions (reactive) Never in nature as lone elements but are in compounds 1 valence electron Li, Na, K, Ru, Cs, Fr
14
Group 2: Alkaline-Earth Metals
Hardly in nature as lone elements but are usually in compounds (highly reactive but not as much as Group 1) 2 valence electrons Be, Mg, Ca, Sr, Ba, Ra
15
Groups 3 - 12: Transition Metals
Called d-block elements because in the center of the table Do not always have the same outer configurations but their outer s & d orbitals will have the total amount of electrons as their group number Can 1, 2, or 3 valence e- depending on the element with which it reacts
16
Most reactive nonmetals 7 valence electrons F, Cl, Br, I, At
Group 17: Halogens Most reactive nonmetals 7 valence electrons F, Cl, Br, I, At
17
Group 18: Noble Gases Once call inert gases because once thought to be nonreactive Full set of electrons in outermost energy level Except He, all have config of ns2np6 He, Ne, Ar, Kr, Xe, Rn
18
Lanthanides & Actinides
(La # & Ac # ) Called the f-block elements Lanthanides are similar in reactivity to alkaline-earth metals Actinides are all radioactive due to their unique nuclear structure
19
Most common element in universe (3 of 4 atoms)
Lonely Hydrogen Most common element in universe (3 of 4 atoms) Only 1 electron so reacts with just about anything
20
Metals Most elements are metal
Excellent conductors of electricity & heat Some are brittle; others are ductile (can be made into wire) & malleable (can be hammered into sheets) Can be mixed with other elements to form alloys (mixtures that improve disadvantages of metals)
21
Metallic Characteristics
Metals Nonmetals Metalloids
22
Chemical Reactivity Families
Similar valence e- within a group result in similar chemical properties
23
Chemical Reactivity Alkali Metals Alkaline Earth Metals
Transition Metals Halogens Noble Gases
24
Periodic Properties Atomic Radius size of atom
Measured by half of bond distance © 1998 LOGAL First Ionization Energy Energy required to remove one e- from a neutral atom. © 1998 LOGAL Melting/Boiling Point
25
Atomic Radius Atomic Radius Increases to the LEFT and DOWN
26
Atomic Radius K Na Li Ar Ne
27
Atomic Radius Why radius larger going down?
Higher energy levels have larger orbitals Shielding - core e- block the attraction between the nucleus and the valence e- Why smaller to the right? Increased nuclear charge without additional shielding pulls e- in tighter
28
Ionization Energy First Ionization Energy
Increases UP and to the RIGHT
29
Ionization Energy First Ionization Energy He Ne Ar Li Na K
30
Ionization Energy Why opposite of atomic radius?
In small atoms, e- are close to the nucleus where the attraction is stronger Why small jumps within each group? Stable e- configurations don’t want to lose e-
31
Melting/Boiling Point
Highest in the middle of a period.
32
Ionic Radius Ionic Radius Cations (+) lose e- smaller Anions (–)
gain e- larger © 2002 Prentice-Hall, Inc.
33
Ionic Radius Increases DOWN and to the LEFT for each type of ion
34
Examples Which atom has the larger radius? Be or Ba Ca or Br Ba Ca
35
N or Bi Ba or Ne N Ne Examples
Which atom has the higher 1st Ionization Energy? N or Bi Ba or Ne N Ne
36
Li or C Cr or Kr C Cr Examples
Which atom has the higher melting/boiling point? Li or C Cr or Kr C Cr
37
S or S2- Al or Al3+ S2- Al Examples
Which particle has the larger radius? S or S2- Al or Al3+ S2- Al
38
Electronegativity Numerical value of how much an atom in a molecule attracts electrons Scale created by Linus Pauling Flourine is 4.0 & other elements are calculated relative to this value
39
Electronegativity Increases UP and to the RIGHT
Same as Ionization Energy
40
Electron Affinity The energy change that occurs when a neutral atom gains an electron This is also due to increasing nuclear charge Literally means “love of electrons”
41
Electron Affinity Increases UP and to the RIGHT
Same as Ionization Energy & Electronegativity
42
Examples Which atom is most electronegative? N or Bi Ba or Rb N Ba
43
Be or Ba Ca or Br Be Br Examples
Which atom has the highest electron affinity? Be or Ba Ca or Br Be Br
44
Examples Which atom is more metallic? S or Fr Al or Ge Fr Ge
45
Summary of Trends Ionization Energy, Electronegativity, Electron Affinity all Increase UP & RIGHT Atomic Radius & Ionic Radius all Increase DOWN & LEFT Boiling/Melting point Increases then Decreases across blocks Metals are to the left of the “stairs” & non-metals are to the right
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.