$$\displaystyle \frac{14}{7} \mathrm{N}$$ \text{ and } \frac{18}{7} \mathrm{N}$

Question 1

Which of the following statements best describes an atom?

Accepted Answer

An atom is the smallest particle of an element that retains the chemical properties of that element.

Question 2

Which subatomic particle is responsible for the chemical identity of an element?

Accepted Answer

Proton

Question 3

Given the symbolic representation $$\displaystyle \frac{23}{11} \mathrm{Na}$$, how many neutrons does this atom have?

Accepted Answer

$$12$$

Question 4

A neutral atom of zinc has a mass number of $$65$$ and an atomic number of $$30. $$How many electrons does it have?

Accepted Answer

$$30$$

Question 5

Which of the following is an isotope of $$\displaystyle \frac{238}{92} \mathrm{U}$$?

Accepted Answer

$$\displaystyle \frac{239}{92} \mathrm{U}$$

Question 6

Which two notations represent isotopes of the same element?

Accepted Answer

$$\displaystyle \frac{14}{7} \mathrm{N}$$ 	ext{ and } \frac{18}{7} \mathrm{N}$

Question 7

Which group on the periodic table contains the least reactive elements?

Accepted Answer

Group 8A (noble gases)

Question 8

How many protons, neutrons, and electrons are in an atom of gold, $$\displaystyle \frac{197}{79} \mathrm{Au}$$?

Accepted Answer

79 protons, 118 neutrons, 79 electrons

Question 9

Which of the following best explains why isotopes of the same element have identical chemical properties?

Accepted Answer

They have the same number of protons and electrons.

Question 10

A patient undergoes a Tc-99 scan to trace blood flow in the heart. What property of Tc-99 makes it useful for this medical application?

Accepted Answer

It is a radioactive isotope that emits detectable energy.

Question 11

Which of the following elements is in Group 1A of the periodic table?

Accepted Answer

Potassium (K)

Question 12

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its mass number?

Accepted Answer

$$35$$

Question 13

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

Accepted Answer

Electrons are negatively charged and move rapidly outside the nucleus.

Question 14

Which equation correctly relates the mass number ($$A$$), atomic number ($$Z$$), and number of neutrons ($$N) in an $$atom?

Accepted Answer

$$A = Z + N$$

Question 15

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

Accepted Answer

The physical and chemical properties of the elements are periodic functions of their atomic numbers.

Question 16

A neutral atom of boron is represented as $$\displaystyle \frac{11}{5} \mathrm{B}. $$How many electrons does it have?

Accepted Answer

$$5$$

Question 17

Which of the following elements is a halogen?

Accepted Answer

Chlorine (Cl)

Question 18

Which property is shared by all elements in Group 2A (alkaline earth metals)?

Accepted Answer

They have similar chemical properties.

Question 19

If an atom has 26 protons and 29 neutrons, what is its mass number?

Accepted Answer

$$55$$

Question 20

Which of the following best explains why electrons are not included in the calculation of an atom's mass number?

Accepted Answer

Electrons have a much smaller mass compared to protons and neutrons.

Atoms and Elements: Structure, Properties, and the Periodic Table

Guida di studio - Domande di pratica