Parts of the Atom
Forces
Unique Identity of Each Atom
Radioactivity
Difficult Questions!
100
What is a proton?
A particle in the atom’s nucleus that has a positive charge
100
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Electromagnetic forces (attractive force between the negative electrons and the positive protons.)
100
What does the atomic number tell you?
The number of protons in the nucleus of an atom.
100
Define “radioactive.”
When a nucleus of an atom spontaneously breaks up, emitting particles of energy in the process.
100
Find Krypton on the Periodic Table. What is its atomic number? How many neutrons does it have?
The atomic number of Krypton is 36. Krypton has 47 neutrons. (Atomic mass is 83.798.)
200
What is a neutron?
A particle in the atom’s nucleus with no electric charge
200
What is the force that holds all the positively charged protons together in the nucleus?
The strong nuclear force; it attracts the neutrons and the protons to each other.
200
How many electrons does a complete (stable) atom have?
The same as the number of protons.
200
Why does a nucleus become unstable?
If it contains too many or too few neutrons relative to the number of protons.
200
What is the definition of half-life?
A half-life is the time it takes for ½ of an amount of radioactive material to change (decay) into another element.
300
What is an electron?
A particle inside the atom, but outside the nucleus; it has a negative electric charge
300
Which force inside the atom is the strongest, and how strong is it?
The strong nuclear force, it is the strongest force known to science.
300
What is the atomic mass number?
The number of protons plus the average number of neutrons.
300
When an atomic nucleus decays, what eventually happens?
The atom changes to a more stable form (changes to a different element).
300
Is an ion that lost an electron positive or negative, and why?
An ion that lost an electron is positive, because now the positively charged protons outnumber the negatively charged electrons.
400
Where are the electrons found in the atom?
In a region outside the nucleus called the electron cloud.
400
Rank the four forces inside the atom in order from strongest to weakest.
Strong nuclear force, electromagnetic force, the weak force, and gravity.
400
Many elements have more than 1 isotope. Define isotope.
Isotopes are atoms of the same element containing different numbers of neutrons.
400
Name an element found in nature (not man-made) that is radioactive.
Polonium, Uranium, (elements 84-92) Carbon 14
400
How many elements are naturally found on Earth?
Elements 1- 92.
500
What is the nucleus?
The core at the center of an atom, containing most of the atom’s mass and all of its positive charge.
500
Why isn’t gravity a strong force inside the atom?
Because the particles are so small. Gravity is most easily observed in the behavior of large objects.
500
What is the difference between an isotope and an ion?
An isotope is a form of an element with a different number of neutrons; an ion is a form of an element that has gained or lost electrons.
500
Carbon 14, a radioactive isotope of Carbon, contains how many protons and how many neutrons?
Six protons and eight neutrons.
500
Which elements are radioactive and why?
All the elements with an atomic number greater than 83 - because their nucleus is too large to be held together by the strong force.
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