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17 Cards in this Set

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How does the volume of a nucleus compare to the volume of an atom?
The nucleus is much smaller. Its diameter is about 1/10,000 of the diameter of an atom.
What is true about the number of protons in every isotope of the same element?
The number of protons is the same.
How does the model of the orbiting electrons differ from the model of the cloud of electrons?
The model of the orbits shows that the electrons follow regular paths. The model of the cloud of electrons shows that the electrons may be found anywhere in the area around the nucleus.
Where are the electrons found?
moving around the nucleus
How has scientists' understanding of the atom changed over time?
The model has become more complex and detailed over time.
How does the mass of a nucleus compare to the mass of an atom?
The nucleus contains about 99.9 percent of the total mass of an atom.
How does the number of neutrons affect the atomic mass of an isotope?
The greater the number of neutrons, the greater the atomic mass.
Describe the nucleus of hydrogen-3.
It contains 1 proton and 2 neutrons.
How do the charges of protons and electrons compare?
Protons have a positive electric charge. Electrons have an equal, but negative, charge.
What is at the center of an atom?
the nucleus
Where are the protons and neutrons found?
in the nucleus
About what percent of an atom is made up of empty space?
almost 100 percent
Why do the electrons stay within an atom, and not move away from the nucleus?
The opposite, positive charge of the protons in the nucleus attracts the negatively charged electrons.
What happens if an atom is divided into its parts?
The subatomic particles no longer have the property of the substance of which the atom is part.
What chemicals can you name that are found in our bodies?
possible answers: sugar, salt, oxygen, water
An oxygen atom has eight protons and 7 electrons. Is it a negatively or positively charged ion? Explain.
It is positively charged; the atom has 8 positive charges and 7 negative charges, which give it an overall positive charge.
Why don't the protons in the nucleus repel each other?
They are held together by the strong nuclear force.