Q: A sample of chlorine contains two isotopes: $$^{35}Cl (75.76$$% abundance, mass = 34.97 amu) and $$^{37}Cl (24.24$$% abundance, mass = 36.97 amu). What is the atomic mass of chlorine?

$$(0.7576 \times 34.97) + (0.2424 \times 36.97) = 35.45$$ amu

Q: What is the maximum number of electrons that can occupy the third energy level (n = 3) of an atom?

$$2n^2 = 2$$ \times $$3^2 = 18$

Question 1

A farmer needs to apply a fertilizer containing magnesium to his crops. Which of the following statements about magnesium is correct?

Accepted Answer

Magnesium is a metal and is found in Group 2A of the periodic table.

Question 2

Which element has the atomic symbol 'Au' and is named after its Latin name?

Accepted Answer

Gold

Question 3

Which of the following is the correct electron configuration for sulfur (S)?

Accepted Answer

$$1s^22s^22$p^63s^23$p^4$$

Question 4

A neutral atom of chlorine has an atomic number of 17 and a mass number of 37. How many neutrons does it have?

Accepted Answer

$$37 - 17 = 20$$ neutrons

Question 5

Which of the following statements about the periodic table is correct?

Accepted Answer

Groups are vertical columns and periods are horizontal rows.

Question 6

Which element is most likely to be found in the human body as a macromineral and is essential for bone formation?

Accepted Answer

Calcium (Ca)

Question 7

Which of the following best describes the location and charge of a neutron in an atom?

Accepted Answer

Located in the nucleus, no charge

Question 8

A sample of chlorine contains two isotopes: $$^{35}Cl (75.76$$% abundance, mass = 34.97 amu) and $$^{37}Cl (24.24$$% abundance, mass = 36.97 amu). What is the atomic mass of chlorine?

Accepted Answer

$$(0.7576 	imes 34.97) + (0.2424 	imes 36.97) = 35.45$$ amu

Question 9

Which element has the highest ionization energy among C, N, and Cl?

Accepted Answer

Cl

Question 10

Which of the following elements is a halogen?

Accepted Answer

Chlorine (Cl)

Question 11

Which of the following is the correct electron arrangement for calcium (Ca)?

Accepted Answer

$$2, 8, 8, 2$$

Question 12

Which element is most likely to lose electrons easily and exhibit metallic character?

Accepted Answer

Potassium (K)

Question 13

What is the maximum number of electrons that can occupy the third energy level (n = 3) of an atom?

Accepted Answer

$$2n^2 = 2$$ 	imes $$3^2 = 18$

Question 14

Which of the following statements about atomic size is correct?

Accepted Answer

Atomic size increases from top to bottom within a group.

Question 15

Which element is most likely to be found in Group 1A and is highly reactive with water?

Accepted Answer

Sodium (Na)

Question 16

Which of the following is the correct relationship for a neutral atom?

Accepted Answer

Number of protons = number of electrons

Question 17

Which of the following elements has three valence electrons?

Accepted Answer

Aluminum (Al)

Question 18

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 19

Which element is most likely to be the largest atom among C, N, and Cl?

Accepted Answer

C

Atoms and Elements: Structure, Properties, and Periodic Trends

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