Questions and Answers
What is the smallest unit of matter?
What is the mass of a proton compared to the mass of an electron?
The mass of a proton is the same as the mass of an electron
How many electrons does a neutrally charged atom of vanadium have?
23
What is the mass number of an atom with 4 protons, 4 electrons, and 5 neutrons?
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How many neutrons does an atom of lead with an atomic number of 82 and a mass of 207 have?
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What is the smallest particle of calcium that has the same chemical properties?
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The mass of an atom's electrons is included in the atom's mass number.
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Study Notes
Atomic Structure and Mass
- An atom is the smallest unit of matter, composed of protons, electrons, and neutrons.
- Protons and neutrons reside in the nucleus, while electrons orbit around it.
Proton and Electron Mass
- The mass of a proton is equal to the mass of an electron, but since electrons have a negligible mass, they do not contribute significantly to the total mass of an atom.
Electron Count in Neutrally Charged Atoms
- A neutrally charged atom of vanadium (V), which has 23 protons, will also have 23 electrons to balance the positive charge of the protons.
Calculating Mass Number
- The mass number of an atom is calculated by adding the number of protons and neutrons. For example, an atom with 4 protons, 4 electrons, and 5 neutrons has a mass number of 9.
Neutron Calculation in Lead
- An atom of lead with an atomic number of 82 and a mass of 207 has 125 neutrons. This is determined by subtracting the atomic number from the mass: 207 - 82 = 125.
Smallest Particle of an Element
- The smallest particle of an element that retains its chemical properties is known as an atom. For example, the smallest particle of calcium with its properties is a calcium atom.
Electron Mass and Atom's Total Mass
- The mass contribution of electrons is negligible in comparison to protons and neutrons, which is why the mass of an atom does not include the mass of its electrons.
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Description
Test your knowledge on atomic structure and mass in this quiz! You'll explore the fundamentals of atoms, including protons, neutrons, and electrons, as well as calculation techniques for mass numbers and neutron counts. Perfect for students looking to solidify their understanding of chemistry basics.
