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WorksheetsChemistry & Physics 8th STAAR Review
Total questions: 20
Worksheet time: 2hrs 38mins
Which statement correctly describes the location and charge of the electrons in an atom?
The electrons are inside the nucleus and have no charge.
The electrons are outside the nucleus and have no charge.
The electrons are inside the nucleus and have a negative charge.
The electrons are outside the nucleus and have a negative charge.
What is the TOTAL number of protons, neutrons, and electrons in a potassium, K, atom that has a mass of 40?
58
40
59
19
How many protons, neutrons, and electrons are present in an atom of hafnium, Hf, with a mass number of 178?
72 protons, 178 neutrons, 106 electrons
178 protons, 250 neutrons, 72 electrons
106 protons, 72 neutrons, 106 electrons
72 protons, 106 neutrons, 72 electrons
Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?
(Chemical reactivity depends on the valence electrons)
Boron is the most reactive because it has the most protons.
Flourine is the most reactive because it has 7 electrons in the outer shell.
Silicon is the most reactive because it has an equal number of protons and neutrons.
Gallium is the most reactive because it has many more neutrons than protons.
Based on the information shown in the table, which student's responses are correct?
Student 1
Student 2
Student 3
Student 4
Students were asked to identify the location of elements in the periodic table based on clues. Based on the data, which periodic table shows the correct location of the four elements?
Which properties describes the elements in Group 18?
They are chemically stable and liquid at room temperature.
They have eight valence electrons and are flammable.
They are magnetic and boil at low temperatures.
They are gaseous at room temperature and chemically stable.
Which two elements on the periodic table are in the same period?
(At the end of a sentence you place a PERIOD)
Sn (50) and Rb (37)
F (9) and Cl (17)
K (19) and Ba (56)
Se (34) and Te (52)
A student is studying the ways different elements are similar to one another. Which two atoms are of elements with similar chemical properties/reactivity on the periodic table?
(Identify each atom before picking your answer)
Atoms 1 and 2
Atoms 1 and 4
Atoms 2 and 3
Atoms 3 and 4
Students made ball-and-stick models of the substances being studied. The key shows the elements students used in their models. Which model represents an organic compound?
(C H O P S N)
A student listed how different parts of the body work to aid in food digestion. Which of the following is a CHEMICAL change that occurs to the food?
The reduction (gets smaller) in size of food particles as food is chewed.
The movement of food to the stomach after food is swallowed.
The breakdown of molecules of food by enzymes and acid in the stomach.
All of the above
Some students are using samples of different substances for a lab investigation. They plan to observe the physical properties of each substance and record their observations. Which of the substances observed are elements?
(Elements are pure substances found on the periodic table)
S, Fe, O2, Sr, and Al
S, O2, and LiF
N2O4, O2, and LiF
N2O4, Fe, Sr, and Al
Based on the information in the table, which of these statements is NOT TRUE?
A molecule of sorbitol contains three more oxygen atoms than a molecule of glutamine does.
A molecule of lactose contains twice as many atoms as a molecule of fructose does.
A molecule of fructose contains four more atoms than a molecule of glutamine does.
A molecule of lactose contains twice as many carbon atoms as a molecule of sorbitol does.
A student is using colored beads to make a model of aluminum sulfate Al2(SO4)3. Aluminum atoms are represented by blue beads, sulfur atoms by yellow beads, and oxygen atoms by green beads. What combination of beads should the student use for the model?
(the 3 outside the parenthesis needs to be applied to sulfur & oxygen)
6 blue, 3 yellow, 7 green
2 blue, 1 yellow, 4 green
2 blue, 3 yellow, 12 green
6 blue, 12 yellow, 12 green
Strontium phosphate, Sr3(PO4)2, is a crystalline substance used in medicine and industry. How many phosphorus atoms are represented in the formula?
(the 2 outside the parenthesis applies to both phosphorus and oxygen)
4
8
2
6
Which of these formulas contain equal numbers of nitrogen atoms?
(the subscript outside of parenthesis applies to each element inside parenthesis)
Formulas I and III
Formulas I and IV
Formulas II and III
Formulas I, II, and V
A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove the tarnish, students placed the ring in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process. Which observation provides evidence of a chemical reaction?
(City Girls Love Their Phones On)
Hot water heated the aluminum foil
The liquid solution changed color
The pan was lined with aluminum foil
The hot water cooled
Nitrogen dioxide is a gas that can be generated by emissions from vehicles and factories. It can also be generated by natural sources, such as forest fires, lightning, and microbial activity in soil. Which of these provides evidence that a chemical reaction occurs?
A gas is present
The total number of atoms remains unchanged.
The state of matter remains the same
A brown gas is produced
A chemical reaction in which calcium carbonate, CaCO3, is decomposed results in the production of two simpler compounds. What mass of calcium carbonate, to the nearest hundredth of a gram, is decomposed in this reaction?
(Law of Conservation of Mass applies)
6.03
615.16
49.97
1.27
A balance and a graduated cyclinder are used to determine the density of a mineral sample. The sample has a mass of 14.7 g and a volume of 2.2 cm3. What is the density of the mineral sample?
(D = m/v)
0.15 g/cm3
32 g/cm3
13 g/cm3
6.7 g/cm3
