Mastering Chemistry: A Molecular Approach

All elements and matter are composed of extremely small particles called:

• Mixtures

• Molecules

• Atoms

• Compounds

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What can you conclude from the fact that scientists continue to update the atomic model?

• Scientists did not have any information about atoms until a few years ago

• Old information about atoms is useless

• Scientists still have no idea what atoms look like

• New information about atoms continues to be discovered

Which particles in atoms have a negative electric charge?

• electrons

• nuclei

• neutrons

• protons

In an atom, the number of protons equals the number of

• neutrons.

• nuclei.

• electrons.

• isotopes.

What holds atoms together in a molecule?

• Gravity

• chemical bonds

• density

• physical bonds

The nucleus of an atom has

• neutrons and electrons

• protons and neutrons

• protons and electrons

• all the above

Using the diagram to identify the letter that shows the proton.

• a

• b

• c

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Using the diagram to identify the letter that shows the electron.

• a

• b

• c

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Which particles in atoms have a positive charge?

• Nuclei

• Neutrons

• Electrons

• Protons

Table sugar and table salt are examples of

• atoms.

• elements.

• mixtures.

• compounds.

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