1.
What does the nucleus of an atom consist of? Choose the best 2 answers.
Correct Answer(s)
B. Neutrons
C. Protons
Explanation
The nucleus of an atoms contains protons and neutrons. Electrons are always found outside of the nucleus. A photon is a small particle of light.
2.
An electron has a __________ charge.
Correct Answer
A. Negative
Explanation
An electron always has a negative charge.
3.
Which two gasses below are characterized as noble gasses on the Periodic Table?
Correct Answer(s)
A. Argon
B. Xenon
Explanation
Argon and xenon are noble gases, which are found in Group 18 of the Periodic Table. These gases are characterized by their lack of chemical reactivity due to having a full valence electron shell. This makes them stable and unlikely to form compounds under standard conditions. Argon is commonly used in lighting and welding, while xenon is used in specialized light sources and medical imaging.
4.
How is a stable hydrogen atom different from every other atom? Choose the best answer.
Correct Answer
D. It does not need a neutron.
Explanation
A hydrogen atoms does not need a neutron in it's stable form. All other atoms need the same number of protons and neutrons to be stable.
5.
Which two of the following scientists proposed theories about atoms?
Correct Answer(s)
A. Ernest Rutherford
D. Niels Bohr
Explanation
Francis Crick helped to show that DNA had a double helix structure, and Charles Darwin proposed theories of evolution.
6.
What is an element? Choose the best answer.
Correct Answer
C. A substance consisting of only one type of atom
Explanation
For something to be called an "element", it can only contain one type of atom.
7.
What are the only two elements in the first period of the Periodic Table?
Correct Answer(s)
A. Hydrogen
C. Helium
Explanation
The first period of the Periodic Table consists of only two elements, hydrogen and helium. Hydrogen is the first element and has an atomic number of 1. It is the lightest and most abundant element in the universe. Helium is the second element in the first period and has an atomic number of 2. It is a noble gas and is known for its low density and low reactivity. These two elements are the only ones present in the first period of the Periodic Table.
8.
What is the atomic number of an atom? Choose the best response.
Correct Answer
B. The number of protons it contains
Explanation
The atomic number of an atom refers to the number of protons it contains. Protons are subatomic particles with a positive charge that are found in the nucleus of an atom. The atomic number determines the identity of the element, as each element has a unique number of protons. Therefore, the best response is "the number of protons it contains."
9.
How would you best describe two atoms that have the same number of protons and electrons, but differing amounts of neutrons?
Correct Answer
A. Isotopes
Explanation
Isotopes are best described as two atoms that have the same number of protons and electrons but differing amounts of neutrons. Isotopes of an element have the same atomic number but different atomic masses. This is because the number of neutrons in the nucleus varies between isotopes, while the number of protons and electrons remains the same.
10.
Which of the following contains more than one type of atom? Choose the best answers.
Correct Answer(s)
B. A compound
C. A human being
Explanation
A compound contains more than one type of atom because it is formed when two or more different elements chemically combine. In the case of a human being, it is made up of various elements such as carbon, oxygen, hydrogen, and nitrogen, among others. Therefore, both a compound and a human being contain more than one type of atom.
11.
What three pieces of information are given one each square of a typical Periodic Table?
Correct Answer(s)
A. Atomic symbol
B. Atomic number
D. Atomic weight
Explanation
The three pieces of information given in each square of a typical Periodic Table are the atomic symbol, which represents the chemical element, the atomic number, which indicates the number of protons in the nucleus of the atom, and the atomic weight, which represents the average mass of the atom. The atomic charge is not typically provided in the Periodic Table as it can vary depending on the specific ion or isotope of the element.
12.
How would you best define valence electrons?
Correct Answer
A. The electrons in the outer energy level of an atom
Explanation
Valence electrons are located in the outer energy level of the atoms. These are the electrons that are involved in bonding.
13.
What terms describes an atoms that has gained or lost an electron?
Correct Answer
D. An ion
Explanation
An ion is a term used to describe an atom that has gained or lost an electron. When an atom gains an electron, it becomes negatively charged and is called a negative ion or an anion. On the other hand, when an atom loses an electron, it becomes positively charged and is called a positive ion or a cation. Ions play a crucial role in chemical reactions and the formation of compounds.
14.
Choose the two responses that best describe an atom.
Correct Answer(s)
A. Atoms are the small building blocks of all matter.
B. Atoms contain protons, neutrons, and electrons.
Explanation
Atoms are the smallest building blocks of all matter. Atoms are found in everything in our solar system including non-living things.
15.
What is the difference between covalent bonds and ionic bonds? Choose the best response.
Correct Answer
D. In covalent bonds, electrons are shared between atoms. In ionic bonds, electrons are transferred from one atom to another.
Explanation
Covalent bonds involve the sharing of electrons between atoms, while ionic bonds involve the transfer of electrons from one atom to another. This means that in covalent bonds, the electrons are shared, while in ionic bonds, the electrons are transferred. This is the key difference between the two types of bonds.
16.
In a stable atom, the number of protons equals the number of electrons.
Correct Answer
A. True
Explanation
In a stable atom, the number of protons equals the number of electrons. This is because protons have a positive charge, while electrons have a negative charge. The positive charge of the protons is balanced by the negative charge of the electrons, resulting in a neutral atom. If the number of protons and electrons were not equal, the atom would have a net charge and would be considered an ion, rather than a stable atom. Therefore, the statement is true.
17.
Column 18 of the Periodic Table, the noble gasses, contains the most reactive of all the atoms.
Correct Answer
B. False
Explanation
The noble gasses are the last reactive of all the atoms of the Periodic Table.
18.
Two atoms covalently bonded together are more stable than individual atoms.
Correct Answer
A. True
Explanation
When two atoms form a covalent bond, they share electrons, which results in a more stable configuration. This stability is achieved because the shared electrons help to fill the outermost electron shells of both atoms, satisfying the octet rule. By sharing electrons, the atoms achieve a lower energy state and become more stable compared to when they were individual atoms. Therefore, the statement that two atoms covalently bonded together are more stable than individual atoms is true.
19.
At atom that loses an electron has a positive charge.
Correct Answer
A. True
Explanation
When an atom loses an electron, it becomes positively charged because it now has more protons than electrons. Protons carry a positive charge, while electrons carry a negative charge. Therefore, the atom's positive charge is equal to the number of protons minus the number of electrons. This is known as a cation, which is a positively charged ion.
20.
In the Periodic Table, horizontal rows are called groups and vertical columns are called periods.
Correct Answer
B. False
Explanation
Horizontal rows are called periods and vertical columns are called groups.
21.
Electrons are found both inside and outside the nucleus of the atom.
Correct Answer
B. False
Explanation
Electrons are actually found only outside the nucleus of an atom. The nucleus contains protons and neutrons, while electrons occupy the electron shells or energy levels surrounding the nucleus. These negatively charged particles are attracted to the positively charged protons in the nucleus, creating a stable atomic structure. Therefore, the statement that electrons are found both inside and outside the nucleus is false.
22.
A compound is a substance made up of different types of elements.
Correct Answer
A. True
Explanation
A compound is indeed a substance formed by the combination of two or more different types of elements. These elements are chemically bonded together in specific ratios, creating a new substance with unique properties. Examples of compounds include water (H2O) and carbon dioxide (CO2), which are composed of hydrogen and oxygen, and carbon and oxygen, respectively. Therefore, the statement "A compound is a substance made up of different types of elements" is true.