15 Questions
What defines the atomic number of an atom?
Number of protons
What is the mass number of an atom defined by?
Number of protons + Number of neutrons
Which subatomic particle has a negative charge and essentially 0 atomic mass units?
Electron
What symbol is used to represent the atomic number of an element?
$Z$
What is the charge and location of a proton within an atom?
+1, nucleus
What is the atomic number of an element?
The number of protons in the nucleus
What does the mass number represent for a single atom?
The total number of protons and neutrons in the nucleus
What is atomic mass based on?
Relative frequency of different isotopes in nature
What are atoms of different elements with the same atomic mass known as?
Isobars
What does atomic mass represent for an element?
Weighted average of mass numbers of all atoms of the element
What is the correct definition of the atomic number?
The number of protons in an atom
Which statement accurately describes the mass number?
The sum of protons and neutrons in an atom's nucleus
How can the number of neutrons in an atom be determined?
$ ext{Number of neutrons} = ext{Mass number} - ext{Atomic number}$
Which factor determines an element's identity?
Atomic number
How is the mass number calculated for an atom?
The sum of the atomic number and the number of neutrons in an atom
Study Notes
- Atoms have subatomic particles called electrons, protons, and neutrons.
- Electrons travel in orbitals outside the nucleus, have no charge, and a mass of approximately one atomic mass unit.
- Protons have a positive charge, are located in the nucleus, and have a mass of one atomic mass unit.
- Neutrons have no charge, are located in the nucleus, and have a mass of one atomic mass unit.
- The atomic number is the number of protons in an atom and can be found on the periodic table.
- The mass number is the sum of the protons and neutrons in an atom's nucleus and can vary for different isotopes of the same element.
- The atomic number and mass number can be used together to determine the number of neutrons in an atom.
- An element's identity is determined by its atomic number, which is the number of protons in its nucleus.
- Atoms of the same element with different numbers of neutrons are called isotopes and have different mass numbers.
- An atom can be represented by its element symbol, atomic number, and/or mass number.
- The mass number can be calculated as the sum of the atomic number and the number of neutrons in an atom.
- Knowing the atomic and mass numbers of an atom can help determine the number of neutrons in the atom.
Learn about the atomic number and mass number of atoms, which are determined by the number of protons and the total number of protons and neutrons respectively. Understand how these fundamental properties define the identity of different elements.
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