Chemistry DP Past Paper PDF Practice Questions

## Chemistry MCQ Practice Questions ### Chemistry DP #### Which description of the atom is based on the results of the gold foil experiment in the early 1900s? 1. Atoms are small, dense, indivisible spheres. 2. Atoms are composed of protons, electrons, and neutrons. 3. Atoms have small, dense, posi...

## Chemistry MCQ Practice Questions ### Chemistry DP #### Which description of the atom is based on the results of the gold foil experiment in the early 1900s? 1. Atoms are small, dense, indivisible spheres. 2. Atoms are composed of protons, electrons, and neutrons. 3. Atoms have small, dense, positively charged nuclei. 4. Atoms have electrons with wavelike properties. #### Which statement describes a chemical property of sodium? 1. It is silver in color. 2. It has a density of 0.97 g/cm³ at room temperature. 3. It has atoms with an atomic radius of 160 pm. 4. It is highly reactive with water. #### According to the electron cloud model, which term is defined as the most probable location of an electron in an atom? 1. configuration 2. nucleus 3. orbital 4. spectrum #### Which change occurs when an electron returns from a higher energy state to a lower energy state? 1. An ionic compound is formed, and energy is emitted. 2. An ionic compound is formed, and energy is absorbed. 3. A specific amount of energy is absorbed. 4. A specific amount of energy is emitted. #### Which phrase describes the different isotopes of an element? 1. same number of electrons and a different number of protons 2. same number of protons and a different number of electrons 3. same number of protons and a different number of neutrons 4. same number of neutrons and a different number of protons #### What information about C4H10 can be determined from its structural formula but not determined from its molecular formula? 1. physical state 2. molar mass 3. ratio of different atoms 4. arrangement of the atoms #### Oxygen can exist as diatomic oxygen gas, O2(g), or ozone, O3(g). These two forms of oxygen have 1. the same molecular structure and the same properties 2. different molecular structures and different properties 3. the same molecular structure and different properties 4. different molecular structures and the same properties #### Which formula contains a polyatomic ion? 1. KCN 2. K2S 3. AlBr3 4. Al2O3 #### At STP, which substance has metallic bonding? 1. argon 2. barium chloride 3. sulfur dioxide 4. titanium #### How many pairs of electrons are shared between the nitrogen atoms in a molecule of N2? 1. 1 2. 2 3. 3 4. 4 #### Which formula represents a molecule with an asymmetrical distribution of charge? 1. Cl2 2. CO2 3. CH4 4. H₂O #### The electronegativity difference between the atoms in a molecule of HF can be used to determine the 1. energy of the molecule 2. functional group of molecule 3. polarity of the bond in the molecule 4. volume of the atoms in the molecule #### Which compound has the weakest intermolecular forces at 75°C? 1. ethanoic acid 2. ethanol 3. propanone 4. water #### Which term identifies a force of attraction that exists between molecules of water? 1. covalent bonding 2. hydrogen bonding 3. ionic bonding 4. metallic bonding #### The numbers of protons, neutrons, and electrons in each of four different ions are shown in the table below. | Ion | Number of Protons | Number of Neutrons | Number of Electrons | |---|---|---|---| | A | 49 | 60 | 46 | | E | 50 | 70 | 46 | | G | 50 | 69 | 48 | | Z | 51 | 59 | 48 | #### Which ion has the greatest mass? 1. A 2. E 3. G 4. Z #### The mass of a sample of nickel is determined to be 20.40 grams. How many significant figures are used to express this mass? 1. 1 2. 2 3. 3 4. 4 #### What is a chemical name for the compound PbO2? 1. lead(I) oxide 2. lead(II) oxide 3. lead(III) oxide 4. lead(IV) oxide #### Which formula is the empirical formula for ethane, C2H6? 1. CH 2. CH3 3. C2H6 4. C4H12 #### Which phrase describes the nucleus of any atom? 1. has an overall positive charge 2. has an overall negative charge 3. contains negative electrons 4. contains positive electrons #### Which two particles each have a mass of approximately one atomic mass unit? 1. an electron and a proton 2. an electron and a positron 3. a neutron and a proton 4. a neutron and a positron #### The wave-mechanical model of the atom describes the location of electrons 1. as loosely packed in the nucleus of an atom 2. as densely packed in the nucleus of an atom 3. in circular paths around the nucleus 4. in orbitals outside the nucleus #### When a ground state electron in an atom moves to an excited state, the electron 1. absorbs energy as it moves to a higher energy state 2. absorbs energy as it moves to a lower energy state 3. releases energy as it moves to a higher energy state 4. releases energy as it moves to a lower energy state #### Diamond and graphite are two forms of solid carbon. These two forms of carbon have 1. different crystal structures and different properties 2. different crystal structures and the same properties 3. the same crystal structure and different properties 4. the same crystal structure and the same properties #### What is the number of electrons shared between the two atoms in an O2 molecule? 1. 6 2. 2 3. 3 4. 4 #### Silicon is an element in Group 14 on the Periodic Table. The atomic mass and natural abundance for the three naturally occurring isotopes of silicon are shown in the table below. | Isotope Notation | Atomic Mass (u) | Natural Abundance (%) | |---|---|---| | Si-28 | 27.98 | 92.22 | | Si-29 | 28.98 | 4.69 | | Si-30 | 29.97 | 3.09 | #### Draw a Lewis electron-dot diagram for an atom of silicon in the ground state. [1] #### Compare the energy of an electron in the first shell of a silicon atom to the energy of an electron in the third shell of the same atom. [1] #### Show a numerical setup for calculating the atomic mass of the element silicon. [1] #### The ionic radii of four Group 17 elements are given in the table below. | Ion | Ionic Radius (pm) | |---|---| | F- | 133 | | Cl- | 181 | | Br- | 196 | | I- | 220 | #### Identify the noble gas that has atoms in the ground state with the same electron configuration as a Br¯ ion in the ground state. [1] #### State, in terms of electrons, why the ionic radius of a Group 17 element is larger than the atomic radius for the same element. [1] #### Which changes in both charge and radius occur when an atom loses an electron? 1. A negative ion is formed with a smaller radius than the atom. 2. A negative ion is formed with a larger radius than the atom. 3. A positive ion is formed with a smaller radius than the atom. 4. A positive ion is formed with a larger radius than the atom. #### Which Lewis electron-dot diagram represents an atom of nitrogen in the ground state? #### The Periodic Table of the Elements has changed over the past 150 years. During this time, many elements have been added as they were discovered. The elements 113, 115, 117, and 118 in Period 7 were named in 2016. Their official names have been approved by the International Union of Pure and Applied Chemistry (IUPAC). The table below lists the names, symbols, and atomic numbers for these four elements. | Element Name | Atomic Number | Element Symbol Prior to 2016 | Element Symbol as of 2016 | |---|---|---|---| | nihonium | 113 | Uut | Nh | | moscovium | 115 | Uup | Mc | | tennessine | 117 | Uus | Ts | | oganesson | 118 | Uuo | Og | #### Identify the element in this table that is located on the Periodic Table of the Elements in the group classified as noble gases. [1] #### Explain, in terms of valence electrons, why the elements nihonium and tennessine would be expected to differ in their chemical properties. [1] #### Describe the general trend in first ionization energy values as the five elements above moscovium in Group 15 on the Periodic Table of the Elements are considered in order of increasing atomic number. [1] #### State, in terms of protons, why tennessine is listed before oganesson in Period 7 on the Periodic Table of the Elements. [1] #### The atomic masses and natural abundances of the two naturally occurring isotopes of silver are shown in the table below. | Isotope | Atomic Mass (u) | Natural Abundance (%) | |---|---|---| | Ag-107 | 106.905 | 51.8 | | Ag-109 | 108.905 | 48.2 | #### Which numerical setup can be used to calculate the atomic mass of silver? 1. (106.905 u) (51.8) + (108.905 u)(48.2) 2. (106.905 u) (51.8%) + (108.905 u) (48.2%) 3. (106.905 u) (48.2) + (108.905 u) (51.8) 4. (106.905 u) (48.2%) + (108.905 u) (51.8%) #### A potassium atom has a mass number of 37. What is the number of neutrons in this atom? 1. 15 2. 18 3. 22 4. 37 #### Compared to the metals in Period 2, the nonmetals in Period 2 have 1. lower first ionization energies and lower electronegativity values 2. lower first ionization energies and higher electronegativity values 3. higher first ionization energies and lower electronegativity values 4. higher first ionization energies and higher electronegativity values #### Which formula represents calcium hydride? 1. CaH 2. CaH2 3. CaOH 4. Ca(OH)2 #### What is the number of moles in a 78.8-gram sample of MgCO3 (gram-formula mass = 84.3 g/mol)? 1. 0.949 mol 2. 0.935 mol 3. 0.843 mol 4. 1.070 mol #### How many moles of KI are needed to make 0.50 L of a 0.20 M aqueous solution? 1. 0.10 mol 2. 0.25 mol 3. 0.40 mol 4. 0.70 mol #### The element technetium, Tc, has several isotopes. The bright-line spectrum of technetium has been observed in the spectra of some stars. #### 51 Compare the energy of an electron in the first shell of a technetium atom to the energy of an electron in the third shell of the same atom. [1] #### 52 State, in terms of protons and neutrons, why the various nuclides of technetium are isotopes of each other. [1] #### The elements on the Periodic Table of the Elements are arranged in order of increasing 1. atomic mass 2. atomic number 3. mass number 4. oxidation state #### Atoms of which element in Group 15 have the greatest electronegativity? 1. As 2. Bi 3. N 4. P #### What is the molecular formula for CH3CH2COOCH3? 1. C2H4O 2. C2H4O2 3. CHO 4. C4H8O2 #### Which chemical bond is most polar? 1. a O-H bond in H₂O 2. a S-H bond in H2S 3. a Se-H bond in H2Se 4. a Te-H bond in H₂Te #### Which phrase describes two atoms that contain the same number of protons but a different number of neutrons? 1. ions of the same element 2. isotopes of the same element 3. a mixture of different elements 4. nuclides of different elements #### Which electron configuration represents the electrons of a phosphorus atom in an excited state? 1. 2-8-5 2. 2-8-6 3. 2-7-6 4. 2-7-4 #### A substance conducts electricity in the liquid phase but not in the solid phase. This substance can be classified as 1. covalent 2. ionic 3. metallic 4. molecular #### What is the number of protons in an atom with the electron configuration of 2-5? 1. 5 2. 2 3. 3 4. 7 #### In the wave-mechanical model of an atom, an orbital is defined as 1. a region of the most probable neutron location 2. a region of the most probable electron location 3. the straight-line path of a neutron 4. the straight-line path of an electron #### In the ground state, which shell of a potassium atom has an electron with the greatest amount of energy? 1. first 2. second 3. third 4. fourth #### State the general trend for the atomic radius of the first seven elements in Period 3 when considered in order from left to right. [1] #### State, in terms of valence electrons, why aluminum and sulfur have different chemical properties. [1] #### Identify the element in Period 3 that reacts with oxygen to form an ionic compound represented by X in the formula X2O. [1] #### Lithium, beryllium, boron, and fluorine are four elements in Period 2 on the Periodic Table. #### 57 State, in terms of electrons, why the radius of a Be2+ ion is smaller than the radius of a Be atom. [1] #### 58 Draw a Lewis electron-dot diagram for an atom of boron. [1] #### Given the equation representing a reaction: 2H2(g) + 2NO(g) → N2(g) + 2H2O(g) #### What is the mass of N2(g) produced when 1.0 gram of H2(g) completely reacts with 15.0 grams of NO(g) to produce 9.0 grams of H2O(g)? 1. 7.0 g 2. 14.0 g 3. 25.0 g 4. 28.0 g #### An atom of which element bonds with an atom of hydrogen to form the most polar bond? 1. bromine 2. chlorine 3. fluorine 4. iodine #### Given the bright-line spectra of four elements and the spectrum of a mixture formed from two of these elements: #### Which two elements are present in this mixture? 1. A and Q 2. A and E 3. G and Q 4. G and E #### What is the approximate mass of an atom that has 10 electrons, 10 protons, and 9 neutrons? 1. 10. u 2. 19 u 3. 20. u 4. 29 u #### Which electron configuration represents the electrons of an atom in an excited state? 1. 2-7-3 2. 2-8-2 3. 2-8-8-1 4. 2-8-9-2 #### Given information about the naturally occurring isotopes of bromine: | Isotope Notation | Atomic Mass (u) | Natural Abundance (%) | |---|---|---| | Br-79 | 78.92 | 50.69 | | Br-81 | 80.92 | 49.31 | #### Which numerical setup can be used to determine the atomic mass of bromine? 1. (78.92 u) (50.69) + (80.92 u)(49.31) 2. (80.92 u) (50.69) + (78.92 u)(49.31) 3. (78.92 u) (0.5069) + (80.92 u) (0.4931) 4. (80.92 u) (0.5069) + (78.92 u) (0.4931) #### What is a chemical name of the compound CuS? 1. copper(I) sulfide 2. copper(I) sulfate 3. copper(II) sulfide 4. copper(II) sulfate #### Radius (pm) #### Atomic Radii of Period 3 Elements | Element | Radius (pm) | |---|---| | Na | 160 | | Mg | 140 | | AL | 120 | | Si | 110 | | P | 110 | | S | 100 | | Cl | 100 | | Ar | 90 | #### State the general trend for the atomic radius of the first seven elements in Period 3 when considered in order from left to right. [1] #### State, in terms of valence electrons, why aluminum and sulfur have different chemical properties. [1] #### Identify the element in Period 3 that reacts with oxygen to form an ionic compound represented by X in the formula X2O. [1] #### Lithium, beryllium, boron, and fluorine are four elements in Period 2 on the Periodic Table. #### 57 State, in terms of electrons, why the radius of a Be2+ ion is smaller than the radius of a Be atom. [1] #### 58 Draw a Lewis electron-dot diagram for an atom of boron. [1] #### Given the equation representing a reaction: 2H2(g) + 2NO(g) → N2(g) + 2H2O(g) #### What is the mass of N2(g) produced when 1.0 gram of H2(g) completely reacts with 15.0 grams of NO(g) to produce 9.0 grams of H2O(g)? 1. 7.0 g 2. 14.0 g 3. 25.0 g 4. 28.0 g #### An atom of which element bonds with an atom of hydrogen to form the most polar bond? 1. bromine 2. chlorine 3. fluorine 4. iodine