4.2 - Valence Electrons & Electron-DOT Diagrams Quiz

1. A new element, Uuo, is one of the elements in Group 18. Which of the following correctly states how many valence electrons would be expected in an atom of the element Uuo in the ground state and provides the best reasoning?

Both (A) and (C)

Remember: Elements of the same group tend to have the same number of valence electrons. To find the number of valence electrons in an element, determine its group number and look at the number of valence electrons that each element has in that group to find how many valence electrons there are in the element you are examining.

Explanation

Remember: Elements of the same group tend to have the same number of valence electrons. To find the number of valence electrons in an element, determine its group number and look at the number of valence electrons that each element has in that group to find how many valence electrons there are in the element you are examining.

2. Which of the following is the correct electron-dot diagram for an atom with an electron configuration of 2-8-18-5?

Remember: Find the number of valence electrons by looking at the number of electrons in the last electron shell/energy level of the ground-state configuration. Then, draw the valence electrons around the central atom.

Explanation

Remember: Find the number of valence electrons by looking at the number of electrons in the last electron shell/energy level of the ground-state configuration. Then, draw the valence electrons around the central atom.

3. Which of the following is the correct electron-dot diagram for an atom with an electron configuration of 2-8-18-7?

The correct electron-dot diagram for an atom with an electron configuration of 2-8-18-7 would have two dots in the first energy level, eight dots in the second energy level, eighteen dots in the third energy level, and seven dots in the fourth energy level. This represents the arrangement of electrons in the atom's orbitals, with each dot representing one electron.

Explanation

The correct electron-dot diagram for an atom with an electron configuration of 2-8-18-7 would have two dots in the first energy level, eight dots in the second energy level, eighteen dots in the third energy level, and seven dots in the fourth energy level. This represents the arrangement of electrons in the atom's orbitals, with each dot representing one electron.

4. Which of the following represents an atom of chlorine in the ground state?

Remember: Find the number of valence electrons by looking at the number of electrons in the last electron shell/energy level of the ground-state configuration. Then, draw the valence electrons around the central atom.

Explanation

Remember: Find the number of valence electrons by looking at the number of electrons in the last electron shell/energy level of the ground-state configuration. Then, draw the valence electrons around the central atom.

5. Carbon and element Y have similar chemical properties. Which of the following correctly represents one possible configuration of element Y?

2-6

2-8-18-4

2-8-8

2-2

For two elements to have similar chemical properties, they MUST have the same number of valence electrons AND typically be in the same group. Remember that valence electrons are the electrons in the outermost (last) electron shell/energy level. Carbon, in this example, has a ground-state configuration of 2-4, so element Y must also have 4 valence electrons (4 as the last number in its configuration) to have similar chemical properties.

Explanation

For two elements to have similar chemical properties, they MUST have the same number of valence electrons AND typically be in the same group. Remember that valence electrons are the electrons in the outermost (last) electron shell/energy level. Carbon, in this example, has a ground-state configuration of 2-4, so element Y must also have 4 valence electrons (4 as the last number in its configuration) to have similar chemical properties.

6. Which of the following is an element with similar chemical properties to that of boron?

Carbon

Germanium

Magnesium

Nitrogen

Gallium

For two elements to have similar chemical properties (i.e., how they form bonds), they must ALWAYS have the same number of valence electrons. A lot of the time, the group numbers of both elements with similar chemical properties are also the same, though the number of valence electrons being the same is the most important reason why they have similar chemical properties, in terms of atomic structure.

Explanation

For two elements to have similar chemical properties (i.e., how they form bonds), they must ALWAYS have the same number of valence electrons. A lot of the time, the group numbers of both elements with similar chemical properties are also the same, though the number of valence electrons being the same is the most important reason why they have similar chemical properties, in terms of atomic structure.

7. In the ground state, an atom of which element has 2 valence electrons? (Hint: Use Table S to change element names to symbols!)

Copper

Boron

Tungsten

Cesium

The valence electrons are electrons in the outermost energy level or electron shell of an atom of an element. Look at the last number in the ground-state configuration of the element to find the number of valence electrons.

Explanation

The valence electrons are electrons in the outermost energy level or electron shell of an atom of an element. Look at the last number in the ground-state configuration of the element to find the number of valence electrons.