WorksheetsUNIT 1 REVIEW (7TH GRADE)
Total questions: 12
Worksheet time: 32mins
A student is writing a report on the properties of fluorine. She decides to include a brief section about other elements that are similar to fluorine. In order to find similar elements, she looks up where fluorine is located on the periodic table of elements shown below. The student wants to select the elements similar to fluorine. Which of the following sets of elements should be included?
Helium, sulfur, and argon, because they are diagonal from fluorine.
Oxygen, neon, and chlorine, because they are connected to fluorine.
Nitrogen, oxygen, and neon, because they are in the same row as fluorine.
Chlorine, bromine, and iodine, because they are in the same column as fluorine.
Throughout history, scientists have been known to copy ideas from their peers. Dmitry Mendeleev was no exception—he arranged all of the elements known at the time according to their atomic masses, just as Johann Döbereiner and John Newlands did before him. However, Mendeleev intentionally left blank spaces in his working version of the periodic table of elements. Which statement best explains the importance of the blank spaces in Mendeleev’s version of the periodic table of elements?
They predicted the existence of elements that had not yet been discovered.
They were used to prevent other scientists from accusing him of plagiarism.
They established a different method for arranging newly discovered elements.
They represented errors that other scientists had made when arranging the elements.
The alkaline earth metals are a group of shiny, silvery-white elements that share several properties. Provided below is an incomplete data table listing the atomic masses of the first three alkaline earth metals, arranged from lightest to heaviest. Look at the table then choose which of the following would be a reasonable estimate for the atomic mass of magnesium (Mg). (Hint: Some groups of three elements with similar properties show a pattern in which, when arranged in order by atomic mass, the middle element has properties that are in between the properties of the other two.)
10
25
39
41
In the 1800s, pure aluminum metal was so valuable that it was worth as much as gold! Now, aluminum is relatively cheap and can be used to make all sorts of products, like the aluminum cans shown below. To avoid using very large numbers, or very small numbers, people choose a unit appropriate to the scale of the object. The mass of only one can could be measured in grams, but the large block of recycled cans would more likely be measured in kilograms. Which of the following units would be most appropriate for measuring mass at the scale of a single aluminum atom?
Daltons
Ounces
Milligrams
Pounds
What system did Mendeleev use to arrange the elements according to their properties?
He renamed them and arranged them in alphabetical order.
He grouped them together in diagrams according to their properties.
He arranged the elements by columns according to their properties.
He arranged them according to the largest to smallest atomic numbers.
What did Mendeleev do when he came across an element that did not share properties with its column?
He created new elements to fill in the blank spaces left in the column.
He started over until he could figure out where all the elements fit next to each other.
He waited until the next element in the column was discovered before continuing his work.
He left a blank space because he hypothesized it was an element that had not been discovered.
Limonene is a colorless chemical that is commonly found in citrus fruits. It has two forms: R-limonene, which smells like oranges, and S-limonene, which smells like lemons. Both forms of limonene have exactly the same number of carbon, hydrogen, and oxygen atoms. Which of the following is the most likely explanation for why the two forms of limonene smell different?
The two forms have different arrangement of atoms.
The two forms have different chemical bonds.
The two forms have a different ratio of atoms.
The two forms have different types of atoms.
Nitrogen and oxygen can combine to form many useful molecules, such as the nitrous oxide (also known as “laughing gas”) used in dental offices. Provided below is a ball-and-stick model of nitrous oxide. Which statement best explains why nitrous oxide (N2O) has very different properties from nitrogen monoxide (NO) and nitrogen dioxide (NO2)?
They all have different chemical bonds
They all have different arrangements of atoms.
They are all composed of different types of atoms
They are all composed of different ratios of atoms.
A group of students are looking at sugar and salt crystals. They have learned that crystals are repeated patterns built up out of subunits. One student notices the salt crystals have 90 degree angles between the sides while the sugar crystals have some different angles. Which of the following best explains the differences in shape between sugar and salt crystals?
Both types of molecules form different angles at random.
The subunits of sugar molecules and salt molecules are different shapes.
Sugar comes from living organisms and salt comes from non-living sources.
Manufactures make the crystals that way to tell them apart in the factory.
A student was playing with a molecular model kit, and built the molecule shown below. According to her science teacher, she had just built the molecular model for acetone (C3H6O), the main chemical in nail polish remover. Her teacher then challenged her to build the molecular model for isopropanol (C3H8O), also known as rubbing alcohol. Using the same colored balls as the ones in the model shown above, how many of each would be needed to build the predicted molecular model for isopropanol?
8 black balls, 3 white balls, 1 red ball
3 black balls, 8 white balls, 1 red ball
8 black balls, 1 white ball, 3 red balls
3 black balls, 1 white ball, 8 red balls
A student is a writing a research report on how plastic is produced, and finds out that certain types of plastic are made from a chemical called 1-butene (C4H8). The ball-and-stick model of 1-butene is shown below on the left. The student decides to build another model. Which of the following ball-and-stick models has the same atomic composition as, but different properties from, 1-butene?
Model A
Model B
Model C
Model D
A scientist decides to use X-ray crystallography to examine a sample of sodium chloride (also known as table salt) that he recently made in his laboratory. He also decides to use this technique to look at a sample of sodium chloride that he extracted from seawater. How will the X-ray crystallography patterns of the two samples compare?
They are the same because the samples are composed of the same elements.
They are the same because the samples have the same atomic arrangement.
They are different because the samples are composed of different elements.
They are different because the samples have a different atomic arrangement.
