Chemistry Atomic Theory Pretest

A nucleus is?

A nucleus is the central part of an atom. containing protons and neutrons.

A neutron is?

A neutron is a subatomic particle with no charge.

An electron is?

An electron is a negatively charged subatomic particle.

What is the relative charge of a proton?

A proton has a relative charge of +1.

A proton is?

A proton is a positively charged subatomic particle.

What is the relative mass of an electron?

A) 1/1840 the mass of a hydrogen atom B) 1/1840 the mass of a neutron + a proton C) 1/1840 the mass of a C-12 atom D) 1/1840 the mass of an alpha particle **A) is the correct answer. The relative mass of an electron is 1/1840 the mass of a hydrogen atom.

The mass number of an element whose atoms have 12 protons and 13 neutrons is?

A) 12 C) 25 B) 13 D) 12.5 **C) 25 is the correct answer. The atomic mass is the sum of the protons and the neutrons.

How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain?

A) 50 protons, 50 electrons, 75 neutrons B) 75 electrons, 50 protons, 50 neutrons C) 120 neutrons, 50 protons, 75 electrons D) 70 neutrons, 75 protons, 50 electrons **A) is the correct answer. An atom with atomic number 50 and mass number 125 contains 50 protons, 50 electrons, 75 neutrons.

The atomic number of an element whose atoms have 9 protons and 10 neutrons is?

A) 9 C) 10 B) 19 D) 18 **A) 9 is the correct answer. The atomic number equals the number of protons.

Dalton's atomic theory included which idea?

A) All atoms of all elements are the same size. B) Atoms of different elements always combine in one-to-one ratios. C) Atoms of the same element are always identical. D) Individual atoms can be seen with a microscope. ** C) is the correct answer. Dalton's atomic theory said atoms of the same element are always identical.

Which of the following statements is not a main point of Dalton's atomic theory?

A) All matter is made up of atoms. B) Atoms are made up of smaller particles. C) Atoms are indestructible. D) All atoms of one element are exactly alike, but they are different from atoms of other elements. **B) Atoms are made up of small particles is the correct answer.

The smallest particle of an element that retains the properties of that element is an?

A) Atom C) Proton B) Electron D) Neutron **A) Atom is the correct answer. An atom is the smallest particle of an element that retains the properties of that element.

The sum of the protons and neutrons in an atom equals the ?

A) Atomic number C) Atomic mass B) Nucleus number D) Mass number **D) is the correct answer. The sum of the protons and neutrons in an atom equals the mass number.

Which scientist described an atom made of a solid positively charge with electrons dispersed throughout it?

A) Chadwick C) Rutherford B) Thomson D) Bohr ** B) Thomson is the correct answer. Thomson described an atom made of a solid positively charge with electrons dispersed throughout it.

Which scientist discovered the existence of neutrons?

A) Chadwick C) Rutherford B) Thomson D) Bohr **A) Chadwick is the correct answer. Chadwick discovered the existence of atoms.

Which scientist described a positively charged core (nucleus) surrounded by mostly empty space?

A) Chadwick C) Rutherford B) Thomson D) Bohr **C) Rutherford is the correct answer. Rutherford described a positively charged core (nucleus) surrounded by mostly empty space

Which scientist developed the model of the atom shown in the image box on the side of the answer to this question?

A) Chadwick C) Rutherford B) Thomson D) Bohr B) Thomson is the correct answer.

According to the modern concept of the atom, which are located in the nucleus of the atom?

A) Electrons & protons C) Neutrons & electrons B) Protons only D) Protons & Neutrons **D) Protons & neutrons is the correct answer. Protons and neutrons are located in the nucleus of the atom.

The particles that are found in the nucleus of an atom are?

A) Neutrons & electrons C) Protons & neutrons B) Electrons only. D) Protons & neutrons **C) is the correct answer. Protons & neutrons are found in the nucleus of an atom.

The atomic number of an element is the total number of which particles?

A) Neutrons C) Electrons B) Protons D) Protons & Electrons ** B) is the correct answer. The atomic number of an element is the total number of protons.

Which element has 14 protons?

A) Nitrogen C) Aluminum B) Silicon D) Sulfur **B) Silicon is the correct answer. Silicon has 14 protons.

Isotopes of the same elements have different?

A) Numbers of neutrons C) Numbers of electrons B) Number of protons D) Atomic numbers **A) is the correct answer. Isotopes of the same elements have different numbers of neutrons.

All atoms are

A) Positively charged, with the number of protons exceeding the number of electrons. B) Negatively charged, with the number of electrons exceeding the number of protons. C) Neutral, with the number of protons equaling the number of electrons. D) Neutral, with the number of protons equaling the number of electrons which is equal to the number of neutrons. **C) is the correct answer. All atoms are neutral, with the number of protons equaling the number of electrons.

The only subatomic particle that does not carry an electric charge is the

A) Proton C) Electron B) Neutron D) Nucleus **B) Neutron is the correct answer.

Which subatomic particle has a charge of +1?

A) Proton C) Electron B) atom D) Neutron A) Proton is the correct answer. A proton has a charge of +1.

Which of the following statements in not true?

A) Protons have a positive charge. B) Electrons are negatively charged and have a mass of 1 amu. C) The nucleus of an atom is positively charged. D) Neutrons are located in the nucleus of an atom. **B) is the correct answer. Electrons are negatively charged and have a mass of 1 amu is false.

Who conducted experiments to determine the quality of charge carried by an electron?

A) Rutherford C) Dalton B) Millikan D) Thomson **B) is the correct answer. Millikan conducted experiments to determine the quality of charge carried by an electron.

What does the number 84 in the name krypton-84 represent?

A) The atomic number B) The mass number C) The sum of protons & electrons D) Twice the number of protons **B) is the correct answer. The number 84 in the name krypton-84 represents the mass number.

J.J. Thomson used a cathode ray to discover the?

A) atom C) Proton B) Electron D) Neutron ** B)Electron is the correct answer. J.J. Thomson used a cathode ray to discover the electron.

An atom is?

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

What is the relative charge of an electron?

An electron has a relative charge of -1

True or False: Isotopes are forms of an element that have the same number of protons but a different number of electrons.

False. Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons.

True or False: In a neutral atom, the number of protons is equal to the number of neutrons.

False. The number of protons is equal to the number of electrons.

In the image on the side of this question, A =107, X= Ag, and Z=47, 107 represents the atomic number and 47 represents the atomic mass.

False. 47 represents the atomic number of silver and 107 represents the atomic mass.

True or False: A cathode ray tube consists of a stream of protons.

False. A cathode ray tube consists of a stream of electrons.

True of False: Aristotle named atoms, atoms.

False. Aristotle did not name atoms, atoms.

Isotopes are?

Isotopes are atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom.

Compare and contrast mass number and atomic mass.

Mass number is the total number of protons and neutrons in the nucleus of an atom (it is a whole number). Atomic mass is the weighted mass of all the isotopes of an element (it might not be a whole number).

The box for an element from the periodic table is shown in the image square at the edge of the answer to this question, use it to answer this question, What is the atomic mass?

The atomic mass is 4.

The atomic mass is?

The atomic mass is the weighted average of the masses of the isotopes of an element.

The atomic mass unit is?

The atomic mass unit is one-twelfth the mass of a carbon atom having six protons and six neutrons (C-12).

The box for an element from the periodic table is shown in the image square at the edge of the answer to this question, use it to answer the question, What is the atomic number?

The atomic number is 2.

The atomic number is?

The atomic number is the total number of protons in the nucleus of an element.

The mass number is?

The mass number is the total number of protons and neutrons in a nucleus.

Use the periodic table to determine the number of protons in an atom of barium.

There are 56 protons in barium.

Use the periodic table to determine the number of electrons in an atom of iridium.

There are 77 electrons in an atom of iridium.

Use the periodic table to determine the number of atoms in an atom of gold.

There are 79 electrons in an atom of gold.

True or False. Greek philosophers thought that matter was composed of four elements: air, earth, water, and fire.

True. Greek philosophers thought that matter was composed of four elements: air, earth, water, and fire.

True of False. The mass of a neutron is approximately equal to the mass of a proton.

True. The mass of a neutron is approximately equal to the mass of a proton.