Question 1

Which of the following statements best describes Dalton's atomic theory as it relates to chemical reactions?

Accepted Answer

Chemical reactions change only the way atoms are combined in compounds.

Question 2

A neutral atom of magnesium-24 is represented as $$^{24}_{12}\mathrm{Mg}. $$How many protons, neutrons, and electrons does it contain?

Accepted Answer

12 protons, 12 neutrons, 12 electrons

Question 3

Which of the following best explains why chlorine has an atomic mass of approximately 35.45 amu?

Accepted Answer

The atomic mass is the average of the masses of chlorine-35 and chlorine-37, weighted by their natural abundances.

Question 4

Which group on the periodic table contains elements that are colorless, unreactive gases at room temperature?

Accepted Answer

Group 8A (noble gases)

Question 5

Which of the following electron configurations represents a halogen in its ground state?

Accepted Answer

$$1s^22s^22$p^5$$

Question 6

A sample contains 75.77% chlorine-35 (mass = 34.969 amu) and 24.23% chlorine-37 (mass = 36.966 amu). Calculate the average atomic mass of chlorine.

Accepted Answer

$$35.45\ \mathrm{amu}$$

Question 7

Which of the following statements about subatomic particles is correct?

Accepted Answer

Protons and neutrons are found in the nucleus and have similar masses.

Question 8

Which element is a metalloid in Group 4A (14) of the periodic table?

Accepted Answer

Silicon (Si)

Question 9

How many electrons can be held in all the 3d orbitals of an atom?

Accepted Answer

10

Question 10

Which of the following elements is most likely to have chemical properties similar to sodium (Na)?

Accepted Answer

Potassium (K)

Question 11

Which of the following is the correct abbreviated electron configuration for zinc (Zn, atomic number 30)?

Accepted Answer

$$[Ar]\ 4s^2$\ 3d$$^{10}$$

Question 12

Which of the following best describes the trend in electron configuration for elements in Group 2A (alkaline earth metals)?

Accepted Answer

They all have two electrons in their outermost s orbital.

Question 13

Which of the following is the correct Lewis dot symbol for nitrogen (N)?

Accepted Answer

N with five dots around it

Question 14

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

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 15

Which of the following is a property of metals?

Accepted Answer

Lustrous and malleable

Question 16

A neutral atom has 17 protons, 18 neutrons, and 17 electrons. What is its isotope notation?

Accepted Answer

$$^{35}_{17}\mathrm{Cl}$$

Question 17

Which of the following best describes the difference between a ramp and stairs in the context of electron energy levels?

Accepted Answer

A ramp represents continuous energy, while stairs represent quantized energy levels.

Question 18

Which of the following is the correct order of filling for the first four subshells according to the Aufbau principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s$$

Question 19

Which of the following elements is a halogen in Period 4?

Accepted Answer

Bromine (Br)

Atoms and the Periodic Table: Structured Study Notes

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