Year 9 Science · Unit 2 · Lesson 06
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank to complete the paragraph below. Each word is used only once. Two words in the bank are distractors, you will not need them.
Electrons are arranged in energy around the nucleus of an atom. The outermost shell is called the shell, and the electrons in it are called valence electrons. Atoms that have a outer shell, like the gases helium, neon, and argon, are extremely and rarely react with other elements. Atoms that do not have a full outer shell are ; they gain, lose, or share electrons to reach stability. The way electrons are distributed across an atom's shells is written as its electron , for example sodium is written as 2,8,1.
True or False? Fix the false ones
Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.
Electrons in shell 1 can hold up to 8 electrons.
Correct it:
Noble gases are unreactive because their outer shells are full.
Correct it:
Sodium, with electron configuration 2,8,1, has 1 valence electron it can lose to become stable.
Correct it:
An atom with a full outer shell is highly reactive and quickly bonds with other atoms.
Correct it:
Carbon (2,4) can reach a full outer shell by gaining 4 electrons, losing 4 electrons, or sharing 4 electrons.
Correct it:
1. Write the electron configurations for the following elements. The first one is done for you.
Hydrogen (Z=1): 1 Helium (Z=2): _______ Carbon (Z=6): _______ Chlorine (Z=17): _______
2. Explain why argon (Ar, Z=18) with configuration 2,8,8 is used as a shield gas in welding, while sodium (Na, Z=11) with configuration 2,8,1 would be completely unsuitable for this purpose.
Wrap Up
In one sentence, what was the main idea of this lesson?