Question

question 2. is the following sentence true or false? the group number of a representative element in the periodic table is related to the number of valence electrons it has. question 3. what is an electron - dot structure? question 4. how many valence electrons are in each atom? a) cesium. b) xenon. c) helium. d) radium. e) chlorine. f) gallium. g) selenium. h) germanium. i) nitrogen.

Explanation:

Question 2

In the periodic table, for representative elements (main - group elements), the group number (using the older 1 - 8A numbering system) is equal to the number of valence electrons. For example, Group 1A elements have 1 valence electron, Group 2A elements have 2 valence electrons, and so on up to Group 8A (excluding helium which has 2 valence electrons).

An electron - dot structure (also known as a Lewis dot structure) is a way to represent the valence electrons of an atom. Dots are used to symbolize the valence electrons around the chemical symbol of the element. For example, for a hydrogen atom (\(H\)) with 1 valence electron, its electron - dot structure is \(H\cdot\).

• Cesium (\(Cs\)): It is in Group 1A. Using the 1 - 8A group numbering for representative elements (where group number = number of valence electrons), it has 1 valence electron.
• Xenon (\(Xe\)): It is in Group 8A (noble gas). Most noble gases (except helium) have 8 valence electrons.
• Helium (\(He\)): It is in Group 8A, but due to its electron configuration (\(1s^{2}\)), it has 2 valence electrons.
• Radium (\(Ra\)): It is in Group 2A. So, it has 2 valence electrons.
• Chlorine (\(Cl\)): It is in Group 7A. Thus, it has 7 valence electrons.
• Gallium (\(Ga\)): It is in Group 3A. So, it has 3 valence electrons.
• Selenium (\(Se\)): It is in Group 6A. Therefore, it has 6 valence electrons.
• Germanium (\(Ge\)): It is in Group 4A. Hence, it has 4 valence electrons.
• Nitrogen (\(N\)): It is in Group 5A. So, it has 5 valence electrons.

Answer:

True

Question 3