1.
An ion is formed when an atom
Correct Answer
A. Gains or loses an electron
Explanation
An ion is formed when an atom gains or loses an electron. This process occurs when an atom either accepts an electron from another atom, resulting in a negative charge (anion), or donates an electron to another atom, resulting in a positive charge (cation). This transfer of electrons allows the atom to achieve a stable electron configuration, similar to that of a noble gas.
2.
Ions that are made up of two or more different atoms are called
Correct Answer
A. Polyatomic
Explanation
Polyatomic ions are ions that are composed of two or more different atoms. Unlike cations, which are positively charged ions, and anions, which are negatively charged ions, polyatomic ions can have either a positive or negative charge. These ions are formed when atoms of different elements combine and share electrons to achieve a stable electronic configuration. Examples of polyatomic ions include ammonium (NH4+), sulfate (SO42-), and carbonate (CO32-).
3.
The attraction between two oppositely charged ions, a positively charged metal and a negatively charged nonmetal, is a called a(n)
Correct Answer
A. Ionic bond
Explanation
Ionic bond is the correct answer because it refers to the attraction between two oppositely charged ions, a positively charged metal and a negatively charged nonmetal. In an ionic bond, electrons are transferred from the metal to the nonmetal, resulting in the formation of ions with opposite charges. These ions are then attracted to each other due to their opposite charges, forming a strong bond. Covalent bond refers to the sharing of electrons between atoms, which is not the case in an ionic bond. Fixed charged ion and variable charged ion are not accurate terms for describing the attraction between oppositely charged ions.
4.
When atoms combine together and have a full outer shell or energy level, the atoms have become
Correct Answer
A. Chemically stable
Explanation
When atoms combine together and have a full outer shell or energy level, they become chemically stable. This means that they have achieved a balanced state where they are less likely to react with other atoms or molecules. Having a full outer shell is desirable for atoms because it corresponds to a lower energy state. In this state, atoms are less likely to gain or lose electrons, resulting in a stable configuration. This stability is crucial for the formation of compounds and the maintenance of chemical reactions.
5.
Atoms that will always gain electrons to become stable are found in
Correct Answer
B. Groups 15-17
Explanation
Atoms in groups 15-17 will always gain electrons to become stable because they have fewer electrons in their outermost energy level than the noble gases, which makes them more likely to accept electrons. Group 15 elements (nitrogen family) have 5 valence electrons and need to gain 3 more to achieve a stable octet, while group 16 elements (oxygen family) have 6 valence electrons and need to gain 2 more. Group 17 elements (halogens) have 7 valence electrons and only need to gain 1 more to achieve stability. Therefore, atoms in groups 15-17 have a tendency to gain electrons to reach a stable electron configuration.
6.
Atoms that will always loose electrons to become stable are
Correct Answer
A. Elements in groups 1-13
Explanation
Elements in groups 1-13 will always lose electrons to become stable because they have fewer valence electrons. These elements have 1 to 3 valence electrons and losing them allows them to achieve a stable electron configuration similar to the nearest noble gas. By losing electrons, these elements can achieve a full outer shell and become more stable.
7.
Atoms that are considered stable just by their position on the periodic table are
Correct Answer
D. Elements in group 18
Explanation
Elements in group 18 of the periodic table, also known as the noble gases, are considered stable just by their position. This is because they have a full outer electron shell, making them highly unreactive and unlikely to form chemical bonds with other elements. The full outer electron shell provides them with a stable electron configuration, which is why they are considered stable.
8.
Atoms that have the ability to form more than one ion are called
Correct Answer
B. Variable charged ions
Explanation
Atoms that have the ability to form more than one ion are called variable charged ions. This means that these atoms can lose or gain different numbers of electrons, resulting in ions with varying charges. This is in contrast to fixed charged ions, which always have a specific charge. Variable charged ions are important in chemistry as they can participate in a variety of chemical reactions and form different compounds.
9.
What is the total number of atoms in H2SO4?
Correct Answer
C. 7
Explanation
The correct answer is 7 because H2SO4 consists of 2 hydrogen (H) atoms, 1 sulfur (S) atom, and 4 oxygen (O) atoms. Therefore, the total number of atoms in H2SO4 is 2 + 1 + 4 = 7.
10.
What is the total number of atoms in Al2(SO4)3?
Correct Answer
D. 17
Explanation
The total number of atoms in Al2(SO4)3 can be determined by counting the atoms in each element present in the compound. Al2(SO4)3 consists of 2 atoms of aluminum (Al), 3 atoms of sulfur (S), and 12 atoms of oxygen (O) since there are 4 oxygen atoms in each sulfate (SO4) group. Adding these up, we get a total of 17 atoms in Al2(SO4)3.
11.
What is the charge of Sodium (Na)?
Correct Answer
A. +1
Explanation
The charge of Sodium (Na) is +1 because it belongs to Group 1 of the periodic table, which means it has one valence electron. Sodium readily loses this electron to achieve a stable electron configuration, resulting in a positive charge of +1.
12.
All of the following are properties of an ionic compound accept for
Correct Answer
A. Low melting points
Explanation
Ionic compounds have high melting points due to the strong electrostatic forces of attraction between the positively and negatively charged ions. This is because ionic compounds are made up of ions, which are formed when a metal donates electrons to a nonmetal. These ions are held together in a lattice structure, resulting in a solid crystal with a high melting point. Therefore, the property of having low melting points does not apply to ionic compounds.
13.
What is the charge of Selenium (Se)?
Correct Answer
B. -2
Explanation
The charge of Selenium (Se) is -2. This is because Selenium belongs to Group 16 of the periodic table, also known as the oxygen family. Elements in this group typically gain two electrons to achieve a stable electron configuration, resulting in a charge of -2.
14.
What is the charge of Aluminum (Al)?
Correct Answer
A. +3
Explanation
Aluminum (Al) has a charge of +3 because it belongs to Group 13 in the periodic table, which means it has three valence electrons. In order to achieve stability, aluminum loses these three electrons to form a positive ion with a charge of +3.
15.
What is the charge of Krypton (Kr)?
Correct Answer
C. No charge (stable)
Explanation
Krypton (Kr) is a noble gas, which means it has a full outer electron shell and is therefore stable. Noble gases do not readily gain or lose electrons, so they have no charge. Therefore, the correct answer is "no charge (stable)".
16.
The electron dot diagrams below show the number of valence electrons for each element. Which element will become stable by losing one valence electron.
Correct Answer
A. Sodium (Na)
Explanation
Sodium (Na) will become stable by losing one valence electron because it has only one valence electron in its outermost energy level. Losing this electron will result in a full outer energy level, which is a stable configuration.
17.
The electron dot diagrams below show the number of valence electrons for each element. Which element is considered to be stable?
Correct Answer
B. Argon (Ar)
Explanation
Argon (Ar) is considered to be stable because it has a full outer electron shell. The electron dot diagram shows that it has 8 valence electrons, which is the maximum number of electrons that can occupy the outermost shell. This makes it less likely to react with other elements and more stable compared to Sodium (Na) and Oxygen (O), which have incomplete outer electron shells. Sodium has 1 valence electron and Oxygen has 6 valence electrons, both of which are unstable configurations.
18.
Using the diagram below, identify the one nonmetal that would react with two atoms of sodium to form a stable ionic compound.
Correct Answer
C. Oxygen (O)
Explanation
Oxygen (O) is the correct answer because it is a nonmetal and can gain two electrons to achieve a stable octet configuration, forming the stable ionic compound sodium oxide (Na2O). Sodium (Na) is a metal and tends to lose one electron to achieve a stable configuration, so it cannot react with two atoms of sodium. Argon (Ar) is a noble gas and already has a stable octet configuration, so it does not readily react with other elements.
19.
In a chemical formula, the subscript represents the
Correct Answer
B. Number of atoms of each element
Explanation
The subscript in a chemical formula represents the number of atoms of each element. This is because the subscript indicates the ratio of atoms in a compound, specifying how many atoms of each element are present in a molecule.
20.
The ionic charge (oxidation number) of Fe in Fe2S3 is ___________.
Correct Answer
A. +3
Explanation
In Fe2S3, the compound is neutral overall, meaning the total sum of the charges of all the atoms in the compound must add up to zero. Since Sulfur (S) typically has an oxidation number of -2, and there are three S atoms in Fe2S3, the total negative charge contributed by Sulfur is -6. Therefore, the total positive charge contributed by Iron (Fe) must be +6 to balance out the negative charge. Since there are two Fe atoms in Fe2S3, each Fe atom must have a charge of +3 to balance out the negative charge from Sulfur. Hence, the correct answer is +3.
21.
An atom that has gained an electron to become stable is
Correct Answer
A. A negatively charged ion (anion)
Explanation
When an atom gains an electron, it results in an excess of negative charge compared to positive charge, making the atom negatively charged. This negatively charged atom is called an anion. Anions are formed when non-metal atoms gain electrons to achieve a stable electron configuration, filling their outermost energy level. Therefore, the correct answer is a negatively charged ion (anion).
22.
All elements in the Halogen group (group 17) have a charge of
Correct Answer
C. -1
Explanation
All elements in the Halogen group (group 17) have a charge of -1. This is because elements in this group have 7 valence electrons, and they tend to gain one electron to achieve a stable octet configuration, resulting in a charge of -1. The halogens are highly reactive and readily form ionic compounds by gaining one electron from other elements. Therefore, the correct answer is -1.
23.
When naming an ionic compound, the name of the metal comes first.
Correct Answer
A. True
Explanation
In ionic compounds, the metal is always listed first in the name. This is because the metal is the cation, or positively charged ion, in the compound. The metal gives away its electrons to the non-metal, which becomes the anion, or negatively charged ion. The metal is therefore named first to indicate its presence and to emphasize its role in the compound.
24.
An element in the Alkaline Earth Metal group (charge of +2) would be most likely to form an ionic bond with an element in __________ .
Correct Answer
C. Group 16
Explanation
An element in the Alkaline Earth Metal group (charge of +2) would be most likely to form an ionic bond with an element in Group 16. This is because elements in Group 16, also known as the Oxygen Group, have a charge of -2 when they form ions. The Alkaline Earth Metal with a charge of +2 can easily combine with an element from Group 16 to form a stable ionic compound, with the Alkaline Earth Metal donating its two electrons to the Group 16 element.
25.
The name of the metal Iron III indicates that the charge on the iron ion will be _____. (Hint: use the variable charge ion worksheet).
Correct Answer
A. +3
Explanation
The name "Iron III" indicates that the charge on the iron ion will be +3. This is because the Roman numeral III represents the charge of +3. In chemical compounds, the Roman numerals are used to indicate the oxidation state or charge of the metal ion. Therefore, in this case, the charge on the iron ion is +3.
26.
The name Copper II indicates that the charge on the copper ion will be _____. (Hint: use the variable charge ion worksheet).
Correct Answer
A. +2
Explanation
The name "Copper II" indicates that the charge on the copper ion will be +2. This is because the Roman numeral II represents the charge of the copper ion, which is positive. The Roman numeral II corresponds to a charge of +2, indicating that the copper ion has lost two electrons and has a positive charge of +2.
27.
The suffix added to the nonmetal when naming ionic compounds is
Correct Answer
B. -ide
Explanation
When naming ionic compounds, the suffix "-ide" is added to the nonmetal. This is because the nonmetal accepts electrons from the metal to form an ionic bond. The resulting compound consists of positively charged metal ions and negatively charged nonmetal ions. By adding the suffix "-ide" to the nonmetal's name, it indicates that it is in its negative ion form in the compound.
28.
A positively charged ion is called a(n)
Correct Answer
A. Cation
Explanation
A positively charged ion is called a cation because it has lost one or more electrons, resulting in a net positive charge. Cations are formed when atoms lose electrons and become more positively charged. This positive charge is due to the fact that the number of protons in the nucleus is greater than the number of electrons in the outer shell. Cations are attracted to negatively charged ions or anions, and they play an important role in chemical reactions and the formation of compounds.