WorksheetsScience STAAR Quick Review 8.5 ABCDE
Total questions: 10
Worksheet time: 5mins
Which statement accurately describes the atoms of a specific element?
An indium, In, atom contains 115 protons inside the nucleus and 49 neutrons outside the nucleus.
A scandium Sc, atom contains 45 electrons outside the nucleus and 21 neutrons inside the nucleus.
An aluminium, Al, atom contains 27 electrons and 27 protons inside the nucleus.
A zinc, Zn, atom contains 30 protons inside the nucleus and 30 electrons outside the nucleus.
A Calcium, Ca, atom contains 29 protons inside the nucleus and 29 outside the nucleus
How many protons, neutron, and electrons are present in an atom of hafnium, Hf, with a mass number of 178
72 protons, 178 neutrons, 106 electrons
72 protons, 106 neutrons, 72 electrons
178 protons, 250 neutrons, 72 electrons
106 protons, 72 neutrons, 106 electrons
80 protons, 121 neutrons, 80 electrons
Based on these drawings, which element is the least reactive?
Neon, because it has two energy levels with eight electrons in the second level.
Chlorine, because it has three energy levels with seven electrons in the third energy level.
Gallium, because it has four energy levels with three electrons in the fourth level.
Tin, because it has five energy levels with four electrons in the fifth level.
Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?
Boron is the most reactive because it has the most protons.
Fluorine 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.
Which table was completed correctly?
How many valence electrons are in an atom of each element in Group 15 in the periodic table?
4 valence electrons
5 valence electrons
6 valence electrons
7 valence electrons
8 valence electrons
Which chemical reaction involves the fewest oxygen atoms?
2AgNO3 + K2SO4 --> Ag2SO4 + 2KNO3
4Fe + 6H2O + 3O2 --> 4Fe(OH)3
6CO2 + 6H2O --> C6H12O6 + 6O2
C2H4 + 3O2 --> 2CO2 + 2H2O
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?
6 blue, 3 yellow, 7 green
2 blue, 1 yellow, 4 green
2 blue, 3 yellow, 12 green
6 blue, 12 yellow, 12 green
6 blue, 3 yellow, 12 green
Assuming the students did not make any careless errors, what likely explains these changes in mass
Procedure 1: All the reactants were liquids that evaporated.
Procedure 2: A gas was formed as one product, and it escaped into the air.
Procedure 1: One of the reactants was converted to thermal energy
Procedure 2: All the products were liquids.
Procedure 1: The reactants were liquids with different densities.
Procedure 2: The reactants were combined into only one product.
Procedure 1: One of the products was a gas that escaped into the air.
Procedure 2: A gas from the air reacted with one of the other reactants.
Based on their observations, can the students correctly conclude that a chemical reaction occurred?
No, because the metal strip was still visible
Yes, because a new material of a different color formed on part of the metal strip
No, because the solution stayed blue
Yes, because the volume of the blue solution stayed the same
