science ch1

What is one way scientists are able to tell substances apart if they have similar densities? A. Scientists test melting points or boiling points. B. Scientists measure the surface area of the substances. C. Scientists test the circumference of the individual atoms. D. Scientists freeze the substance and study it after it cracks open.

A. Scientists test melting points or boiling points.

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? A. They predicted the existence of elements that had not yet been discovered. B. They were used to prevent other scientists from accusing him of plagiarism. C. They established a different method for arranging newly discovered elements. D. They represented errors that other scientists had made when arranging the elements.

A. They predicted the existence of elements that had not yet been discovered.

What is one way scientists tell atoms apart when creating models since they all appear as round spheres? A. They use different colors. B. They use different shapes. C. They assign each atom a number. D. They limit the number of atoms they work with to eight.

A. They use different colors.

What is one way to tell metals of the same size and color apart? A. Weigh them for their density. B. Measure their surface area. C. Weigh them for their mass. D. Use a vinegar solution to test their shine.

A. Weigh them for their density.

Scientists use the atomic scale to measure A. size of atoms. B. amount of atoms in an element. C. size of everything that has atoms. D. size of humans compared to atoms.

A. size of atoms.

List the three items of information provided in this periodic table square.

Atomic Symbol Chemical Symbol Name of Element

What is the atomic difference between water (H2O) and hydrogen peroxide (H2O2)? A. The only difference is that they have different structures. B. Hydrogen peroxide has one more oxygen atom than water. C. The only difference is that they have different compositions. D. Atoms in water have stronger bonds than atoms in hydrogen peroxide.

B. Hydrogen peroxide has one more oxygen atom than water.

What happens when an atom makes a connection with another atom? A. Their increase in size makes them visible to the human eye. B. The atoms create a more complex particle called a molecule. C. The atoms become a single atom depending on which one is stronger. D. They undergo a process that causes them to make copies of themselves.

B. The atoms create a more complex particle called a molecule.

What is another term for "substances" that is commonly used? A. agents B. chemicals C. molecules D. picos

B. chemicals

What unit of measurement do scientists use to measure mass? A. centimeters B. kilograms C. picometers D. pounds

B. kilograms

What system did Mendeleev use to arrange the elements according to their properties? A. He renamed them and arranged them in alphabetical order. B. He grouped them together in diagrams according to their properties. C. He arranged the elements by columns according to their properties. D. He arranged them according to the largest to smallest atomic numbers.

C. He arranged the elements by columns according to their properties.

For the last decade, scientists have been working to make atoms of element 119. Scientists predict that once it is made, it will belong to the group known as the alkali metals, which contains elements like lithium, sodium, and potassium. However, all recent efforts to make element 119 have failed because heavy elements tend to be very unstable. Which of the following would be considered a criterion for successfully making atoms of element 119? A. The atoms must be discovered within the next few years. B. The atoms do not cause damage or pollution to the environment. C. The atoms are stable enough to be observed for a set amount of time. D. The atoms can be made using the limited funding provided by the government.

C. The atoms are stable enough to be observed for a set amount of time.

What is a chemical symbol? A. a picture representation of an atomic number B. any notation regarding an element made by a scientist C. a shorthand notation that represents the name of an element D. a sign that tells a scientist how safe it is to handle a particular element

C. a shorthand notation that represents the name of an element

Scientists use patterns in the periodic table to A. figure out how to turn a metal into a gas. B. figure out how many elements there are. C. predict what will happen when two elements mix. D. predict which elements are expensive.

C. predict what will happen when two elements mix.

What determines a molecule's atomic composition? A. the weight of the molecules and their properties B. the size of the molecule and its place on the periodic table C. the types of elements and number of atoms in each element D. the number of atoms in each element and the size of the molecule

C. the types of elements and number of atoms in each element

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? A. Helium, sulfur, and argon, because they are diagonal from fluorine. B. Oxygen, neon, and chlorine, because they are connected to fluorine. C. Nitrogen, oxygen, and neon, because they are in the same row as fluorine. D. Chlorine, bromine, and iodine, because they are in the same column as fluorine.

D. Chlorine, bromine, and iodine, because they are in the same column as fluorine.

What did Mendeleev do when he came across an element that did not share properties with its column? A. He created new elements to fill in the blank spaces left in the column. B. He started over until he could figure out where all the elements fit next to each other. C. He waited until the next element in the column was discovered before continuing his work. D. He left a blank space because he hypothesized it was an element that had not been discovered.

D. He left a blank space because he hypothesized it was an element that had not been discovered.