$$\text{Charge} = +1$$, $$\text{Electrons} = 10$$

$$\text{Charge} = -1$$, $$\text{Electrons} = 10$$

Question 1

Which of the following statements best describes Dalton’s atomic theory as it relates to the composition of water (H$$_2O$$)?

Accepted Answer

Water is composed of hydrogen and oxygen atoms combined in a 2:1 ratio, and these atoms are indivisible and unique to each element.

Question 2

In the cathode ray tube experiment, what evidence indicated that the particles in the rays were negatively charged?

Accepted Answer

The rays were deflected toward the positive plate in an electric field.

Question 3

Which experiment led to the discovery that atoms have a small, dense, positively charged nucleus?

Accepted Answer

Rutherford’s gold foil experiment

Question 4

A neutral atom of sodium (Na) has 11 protons and 11 electrons. If it loses one electron, what is the resulting ion’s charge and electron count?

Accepted Answer

$$	ext{Charge} = +1$$, $$	ext{Electrons} = 10$$

Question 5

Which of the following best explains why metals are good conductors of electricity?

Accepted Answer

Metals have free-moving electrons that allow electric current to pass through.

Question 6

Which element is a metalloid and what property does it share with metals?

Accepted Answer

Silicon; it conducts electricity.

Question 7

A fluorine atom has 9 protons and 9 electrons. After gaining one electron, what is the charge and electron count of the resulting ion?

Accepted Answer

$$	ext{Charge} = -1$$, $$	ext{Electrons} = 10$$

Question 8

Which group of elements is most likely to form basic solutions when reacting with water?

Accepted Answer

Alkali metals (Group 1A)

Question 9

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

Accepted Answer

Elements in the same group have similar chemical and physical properties.

Question 10

A sample contains an ion with 15 protons and 18 electrons. What is the symbol and charge of this ion?

Accepted Answer

$$\mathrm{P}^{3-}$$

Question 11

Which property is NOT characteristic of nonmetals?

Accepted Answer

They are good conductors of electricity.

Question 12

Which of the following ions has the same number of electrons as a neutral argon atom?

Accepted Answer

$$\mathrm{Cl}^-$$

Question 13

Which scientist is credited with organizing the periodic table by recurring properties and predicting the existence of undiscovered elements?

Accepted Answer

Dmitri Mendeleev

Question 14

A calcium ion has 20 protons and 18 electrons. What is its charge?

Accepted Answer

$$2+$$

Question 15

Which of the following best describes the relationship between protons and the identity of an element?

Accepted Answer

The number of protons in the nucleus defines the element.

Question 16

Which of the following is a real-world application of the periodic law?

Accepted Answer

Predicting the chemical properties of undiscovered elements based on their position in the periodic table.

Question 17

Which of the following best explains why noble gases are unreactive?

Accepted Answer

They have a complete outer electron shell, making it difficult to gain or lose electrons.

Question 18

A lead ion has 82 protons and 80 electrons. What is the symbol and charge of this ion?

Accepted Answer

$$\mathrm{Pb}^{2+}$$

Question 19

Which of the following best describes the difference between cations and anions?

Accepted Answer

Cations have more protons than electrons; anions have more electrons than protons.

Question 20

Which of the following is a property of alkali metals that makes them useful in real-world applications such as batteries?

Accepted Answer

They easily lose one electron to form $$+1$$ ions, allowing for efficient charge transfer.

Atoms and Elements: Structure, Properties, and Classification

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