Download presentation
Presentation is loading. Please wait.
Published byLorin Carr Modified over 9 years ago
1
PART 1 DEFINITION AND IMPORTANCE OF PERIODIC TRENDS
2
Periodic trends are trends on the periodic table in properties of elements that you observe when going: 1) left to right across a period (a __________________ trend) or 2) going down a group (a __________________ trend)
3
Why does an atom’s size or ability to lose or gain electrons matter? Trends among elements in the periodic table often involve: 1) their size or 2) their ability to lose or attract electrons
4
Almost all of chemistry is a result of atoms
5
As a result, much of what goes on in our world is at least partly a result of electrons “moving around!”
6
Here is an example of a question we can answer by using periodic trends: WHY ARE ALKALI METALS SO REACTIVE?? When you can answer this question, we’ll view their reactivity by throwing some sodium metal in water!
7
PART 2 PERIODIC TREND: ATOMIC RADIUS
8
The size of an atom is determined by its ATOMIC RADIUS Can you measure atomic radius by simply measuring the distance between the nucleus and the edge of the atom?
9
What is the accepted way for physically measuring atomic radius?
11
ATOMIC RADIUS
12
As you go down a family, the atomic radius INCREASES DECREASES. Why? As you go from left to right in a period, atomic radii INCREASE DECREASE Why? Review Notes on the “Why” of Periodic Trends
13
The more __________ the nucleus pulls on its valence electrons, the __________ the atoms get.
14
PART 3 IONS
15
All of the other trends we will discuss have to do with how easily an atom _______, ________,or________ electrons So – what is formed when an atom gains or loses electrons?
16
Section 6-3 An ___________ is an atom or bonded group of atoms with a positive or negative charge. A positive ion has ________ electrons A negative ion has ________ electrons
17
Section 6-3 NEGATIVE IONS(cont.) When atoms ______________ electrons, they can become larger, because the addition of an electron increases electrostatic repulsion.
18
When atoms _____________ electrons and form positively charged ions, they always become ______________ for two reasons: 1.The loss of a valence electron n can leave an empty outer orbital resulting in a small radius. 2.Electrostatic repulsion decreases allowing the electrons to be pulled closer to the radius. POSITIVE IONS
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.