Chemistry 8 Lesson 10: Chemotherapy
1. Summary of theory
1.1. How is the valence of an element determined?
a. How to determine
1.2. The rule of valence
2. Illustrated exercise
2.1. Form 1: The valency of the substance
2.2. Form 2: Make a chemical formula when you know the valency
2.3. Form 3: Choose the right chemical formula
3.1. Essay exercises
Question 1: Let the compound of X be XO and Y be Na2Y. The formula for XY is
Verse 2: What is the valency of C in CO given the valence Oxygen is II?
Question 3: In P2O5 What is the valence P?
Verse 4: Make a chemical formula knowing the valence of X is I and the number p = e is 13 and Y has an atomic mass of 35.5?
Question 5: What is the chemical formula of Ca(II) with OH(I)?
3.2. Multiple choice exercises
Question 1: Knowing that hydroxide has valence I, which chemical formula is incorrect?
Verse 2: Barium has valence II. Choose the wrong formula
Question 3: In which formula does the Fe atom have valence II?
Verse 4: We have an oxide called CrO. So the salt of chromium has the corresponding valence
Question 5: Choose the wrong sentence
A. Valence is a number that represents the ability of an atom of an element to bind to an atom of another element
B. The valence of an element is determined by the valency of H chosen as the unit and the valence of oxygen is 2 units
C. Valence rule: xa=yb
D. Phosphorus has only IV . valence
After the lesson to know: make the formula of the compound of 2 elements, the valency of the element in the compound.