Atoms, Compounds, And Elements Pretest
This quiz is a pretest to the physical science unit (8th grade level) which covers atomic theory, atomic structure, molecules, compounds, and elements.
- 1.
What contribution to the atomic theory did Neils Bohr make?
- A.
He discovered the electron.
- B.
He theorized a model of atomic structure
- C.
He discovered the proton.
- D.
He viewed an atom for the first time using an instrument.
Correct Answer
B. He theorized a model of atomic structureExplanation
Neils Bohr made a significant contribution to the atomic theory by theorizing a model of atomic structure. His model, known as the Bohr model, proposed that electrons orbit the nucleus in specific energy levels or shells. This model explained the stability of atoms and the emission and absorption of energy by electrons. Bohr's model laid the foundation for understanding the behavior of electrons in atoms and contributed to the development of quantum mechanics.Rate this question:
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- 2.
Which of the following are parts of an atom? (Choose all that apply)
- A.
Neutron
- B.
Compound
- C.
Electron
- D.
Nucleus
- E.
Atomic bond
- F.
Proton
- G.
Element
- H.
Electron shell
Correct Answer(s)
A. Neutron
C. Electron
D. Nucleus
F. Proton
H. Electron shellExplanation
The parts of an atom include the neutron, electron, nucleus, proton, and electron shell. The neutron is a subatomic particle that has no charge, while the electron is a negatively charged particle that orbits the nucleus. The nucleus is the central part of an atom that contains protons and neutrons. Protons are positively charged particles found in the nucleus. The electron shell is the region surrounding the nucleus where electrons are found. Therefore, all of these options are correct.Rate this question:
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- 3.
Where in the atom are the electrons found?
- A.
Inside the nucleus
- B.
Outside the nucleus
- C.
Orbitting through the nucleus
Correct Answer
B. Outside the nucleusExplanation
Electrons are found outside the nucleus of an atom. They orbit around the nucleus in specific energy levels or shells. These shells are arranged in increasing energy levels, with the innermost shell being closest to the nucleus. The electrons are negatively charged particles and are attracted to the positively charged protons in the nucleus. However, they are also repelled by each other, which causes them to occupy different energy levels and maintain a certain distance from the nucleus. This arrangement of electrons outside the nucleus is what gives atoms their chemical properties and allows for the formation of chemical bonds.Rate this question:
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- 4.
What makes an atom able to form a compound?
- A.
Same number of protons as electrons
- B.
Different number of neutrons than protons
- C.
Unfilled outer electron shells
- D.
A positive or negative charge of the nucleus
Correct Answer
C. Unfilled outer electron shellsExplanation
Atoms are able to form compounds when they have unfilled outer electron shells. This is because atoms are constantly seeking stability, and having unfilled outer electron shells makes them more likely to interact with other atoms in order to achieve a full outer shell. By forming compounds, atoms can share, gain, or lose electrons to achieve a stable electron configuration, ultimately increasing their stability and reducing their reactivity.Rate this question:
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- 5.
What charge does the nucleus of the atom have?
- A.
Positive
- B.
Neutral
- C.
Negative
Correct Answer
A. PositiveExplanation
The nucleus of an atom contains positively charged particles called protons. These protons have a positive charge, which is balanced by an equal number of negatively charged electrons in the electron cloud surrounding the nucleus. Therefore, the correct answer is positive, as the nucleus carries a positive charge.Rate this question:
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- 6.
Which scientists was the first to use the term "atom"?
- A.
Democritus
- B.
John Dalton
- C.
JJ Thomson
- D.
Albert Einstein
Correct Answer
B. John DaltonExplanation
John Dalton was the first scientist to use the term "atom." He proposed the atomic theory in the early 19th century, which stated that all matter is composed of small, indivisible particles called atoms. Dalton's theory revolutionized the understanding of chemistry and laid the foundation for modern atomic theory. His work paved the way for further scientific discoveries and advancements in the field of atomic research.Rate this question:
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- 7.
How does an isotope differ from another atom of the same element?
- A.
The number of neutrons is different
- B.
The number of protons is different
- C.
The number of electrons is different
- D.
The shape is different
Correct Answer
A. The number of neutrons is differentExplanation
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that the atomic mass of isotopes varies due to the differing number of neutrons. Therefore, the correct answer is that the number of neutrons is different between isotopes of the same element.Rate this question:
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- 8.
A pure substance that cannot be separated into simpler substances is called a(n)
- A.
Isotope
- B.
Atom
- C.
Element
- D.
Compound
Correct Answer
C. ElementExplanation
An element is a pure substance that cannot be separated into simpler substances. It consists of only one type of atom, which cannot be broken down into smaller particles by chemical means. Isotopes are different forms of the same element that have the same number of protons but different numbers of neutrons. Atoms are the basic units of matter, but they can combine to form compounds. Therefore, the correct answer is element.Rate this question:
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- 9.
A pure substance that is composed of two or more elements that are chemically combined is a(n)
- A.
Isotope
- B.
Atom
- C.
Element
- D.
Compound
Correct Answer
D. CompoundExplanation
A pure substance that is composed of two or more elements that are chemically combined is called a compound. In a compound, the elements are bonded together in a fixed ratio and cannot be separated by physical means. Isotopes are forms of an element with different numbers of neutrons, atoms are the basic units of matter, and elements are substances made up of only one type of atom. Therefore, compound is the correct answer as it best describes a pure substance composed of chemically combined elements.Rate this question:
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- 10.
The particle(s) that make up the mass of an atom is (are)
- A.
Electrons
- B.
Neutrons
- C.
Protons
- D.
Electron shells
Correct Answer(s)
B. Neutrons
C. ProtonsExplanation
The mass of an atom is made up of neutrons and protons. Neutrons have a neutral charge and are located in the nucleus of an atom along with protons, which have a positive charge. Electrons, on the other hand, have a negative charge and are found in electron shells surrounding the nucleus. Therefore, while electrons and electron shells are important components of an atom, they do not contribute to its mass.Rate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Jun 21, 2013Quiz Created by
Traciwilliams
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