What is the atomic number?
Number of protons in a given element
What is the mass number?
Sum of an element's protons and neutrons
What is the atomic mass?
Essentially equal to the mass number, the sum of an element's protons and neutrons
What are isotopes?
-Atoms of a given atomic element (same atomic number) that have different mass numbers
-Differ in number of neutrons
-Most isotopes are identified by the element followed by the mass number (ex: carbon-12)
What are the names of the three isotopes of hydrogen?
Protium, deuterium, and tritium
What is atomic weight?
The weighted average of the naturally occurring isotopes of an element
-Atoms on the periodic table are listed by atomic weight
What did Rutherford do?
First populated that the atom had a dense, positively charged nucleus that made up only a small fraction of the atom's volume
What is the Bohr model of the atom?
-A dense, positively charged nucleus is surrounded by electrons revolving around the nucleus in orbits with distinct energy levels
What is a quantum?
The energy difference between energy levels
-Quantization means that there is not an infinite range of energy levels available to an electron
-Electrons can exist only at certain energy levels
The energy of an electron ______________ the further it is from the nucleus
Increases
What must an electron do to jump from a lower to higher energy level?
It must absorb an amount of energy precisely equal to the energy difference between the two levels
What happens when electrons return from the excited state to the ground state?
-They emit an amount of energy exactly equal to the energy difference between the two levels
-Every element has a characteristic atom emission spectrum
-Sometimes the electromagnetic energy emitted corresponds to a frequency in the visible light range
What is the quantum mechanical model?
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