Patterns Across Periods and Down Groups

Name: Patterns Across Periods and Down Groups
Author: StemPy Lab

Why does carbon make four bonds and oxygen two? Why is a sodium atom bigger than a chlorine atom? In this course we find the valency, the size, the metallic character and the oxides of the elements, and how they change across a period and down a group.

3 lessons, about 1 h 15 min3 simulations10 problems6 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (3 lessons)

Lesson 1about 25 min
Valency and the position of an element
The valency of an element is the number of electrons that it loses, gains or shares to get a full outer shell. It follows the outer electrons: it goes 1, 2, 3, 4, 3, 2, 1, 0 across a period, and it is the same for all of the elements of a group.
1 simulation2 practice questions1 Python program3 problems1 Python lab
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Lesson 2about 25 min
Atomic size and metallic character
The atomic size decreases across a period, because the nucleus has more protons and it pulls the shells closer. It increases down a group, because each new period adds a shell. Metallic character is the tendency to lose electrons: it decreases across a period and increases down a group.
1 simulation2 practice questions1 Python program4 problems1 Python lab1 question set
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Lesson 3about 25 min
Gaining and losing electrons, and the oxides
Across a period, the tendency to lose electrons falls and the tendency to gain electrons rises. Down a group, the tendency to lose electrons rises. The oxides of the metals on the left are basic, and those of non-metals on the right are acidic. Between them, aluminium oxide is amphoteric.
1 simulation2 practice questions1 Python program3 problems1 note
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More onThe Periodic Table › Periodic Trends Structure of the Atom › Electronic Configuration and Valency

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Patterns Across Periods and Down Groups

Course outline (3 lessons)

Valency and the position of an element

Atomic size and metallic character

Gaining and losing electrons, and the oxides

Test Your Learning

Your teacher

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