The “alkaline earth metals” have

1. The “alkaline earth metals” have

a) one valence electron

b) two valence electrons

c) three valence electrons

d) four valence electrons

2. Each horizontal row on the periodic table is called a

a) period.

b) family.

c) group.

d) cohort.

3. How many valence electrons are present in the element with the following ground state electron configuration?
   1s2 2s2 2p3

a) 2

b) 3

c) 5

d) 7

4. How many valence electrons are in a lead atom in the ground state?

a) 2

b) 4

c) 6

d) 8

5. Which of the following corresponds to the excited state configuration for a boron atom?

a) 1s22s22p1

b) 1s32s2

c) 1s22s23s1

d) 1s22s32p2

6. Atoms of which element has the following electron configuration?
   1s2 2s2 2p6 3s1

a) sulfur

b) strontium

c) sodium

d) nitrogen

7. What is the maximum number of electrons that can occupy the 4f sublevel?

a) 2

b) 6

c) 10

d) 14

8. How many orbitals are contained in the 3d sublevel?

a) 2

b) 5

c) 7

d) 10

The Correct Answer and Explanation is :

Let’s go through each question one by one with the correct answers and explanations:

1. The “alkaline earth metals” have
   Correct answer: b) two valence electrons
   Explanation: Alkaline earth metals belong to Group 2 of the periodic table, and elements in this group have two valence electrons. These elements are Be, Mg, Ca, Sr, Ba, and Ra.
2. Each horizontal row on the periodic table is called a
   Correct answer: a) period
   Explanation: The horizontal rows in the periodic table are called periods. There are seven periods in the periodic table, with each period representing the filling of a new electron shell.
3. How many valence electrons are present in the element with the following ground state electron configuration? 1s² 2s² 2p³
   Correct answer: b) 5
   Explanation: This electron configuration corresponds to nitrogen (atomic number 7). The valence electrons are in the second shell (2s² 2p³), so there are 5 valence electrons.
4. How many valence electrons are in a lead atom in the ground state?
   Correct answer: b) 4
   Explanation: Lead (Pb) has an atomic number of 82, and its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p². The electrons in the outermost shell (6s² 6p²) are the valence electrons, so lead has 4 valence electrons.
5. Which of the following corresponds to the excited state configuration for a boron atom?
   Correct answer: c) 1s² 2s² 3s¹
   Explanation: The ground state configuration for boron (atomic number 5) is 1s² 2s² 2p¹. In the excited state, one of the electrons from the 2p orbital can move to the 3s orbital, resulting in 1s² 2s² 3s¹.
6. Atoms of which element has the following electron configuration? 1s² 2s² 2p⁶ 3s¹
   Correct answer: c) sodium
   Explanation: The electron configuration 1s² 2s² 2p⁶ 3s¹ corresponds to sodium (Na), which has an atomic number of 11. Sodium has one electron in its outermost shell (3s¹), making it an alkali metal.
7. What is the maximum number of electrons that can occupy the 4f sublevel?
   Correct answer: d) 14
   Explanation: The 4f sublevel has 7 orbitals, and each orbital can hold a maximum of 2 electrons. Therefore, the maximum number of electrons that can occupy the 4f sublevel is 14.
8. How many orbitals are contained in the 3d sublevel?
   Correct answer: b) 5
   Explanation: The 3d sublevel has 5 orbitals. Each orbital can hold 2 electrons, so the 3d sublevel can hold a total of 10 electrons.

These explanations provide insight into how electron configurations and periodic trends influence the behavior of elements in the periodic table.