What are the main features of an atoms structure?
- Protons+Neutrons make up the nucleus.
- Nucleus is tiny compared with the total volume of an atom.
- Nucleus is extremely dense and makes up almost all of the atoms mas.
- Most of an atom consists of empty space between the tiny nucleus and and the electron shells.
What are the main features of an atoms structure?
- Protons+Neutrons make up the nucleus.
- Nucleus is tiny compared with the total volume of an atom.
- Nucleus is extremely dense and makes up almost all of the atoms mas.
- Most of an atom consists of empty space between the tiny nucleus and and the electron shells.
What are the main features of an atoms structure?
- Protons+Neutrons make up the nucleus.
- Nucleus is tiny compared with the total volume of an atom.
- Nucleus is extremely dense and makes up almost all of the atoms mas.
- Most of an atom consists of empty space between the tiny nucleus and and the electron shells.
What is the relative mass and charge of a proton?
Relative mass = 1
Relative charge = -1
What is the relative mass and charge of a neutron?
Relative mass= 1
Relative charge = 0
What is the relative mass and charge of an electron?
Relative mass = 1/2000
Relative charge = - 1
Isotopes of the same element have?
- Different masses
- The same number of protons and electrons
- different numbers of neutrons in the nucleus.
What two numbers describe an element?
The atomic number(proton number)- the number of protons in the nucleus.
-The mass number(nucleon number) - the number of particles(protons and neutrons) in the nucleus.
How can you work out the number of neutrons an isotope has?
Subtract the mass number by the proton number.
For an isotope, relative isotopic mass=
atomic mass
When measuring atoms masses by comparing them to carbon-12, what assumptions have been made?
- We have neglected the tiny contribution that electrons make to the mass of an atom.
- We have taken the masses of both a proton and a neutron as 1.0u.
What does the weighted mean mass mean?
Most elements contain a mixture of isotopes, each in a different amount and with a different mass. We use the term “weighted mean mass” to account for the contribution made by each isotope to the overall mass of an element.
What does the contribution made by an isotope to the overall mass depend on?
- the percentage abundance of the isotope
- the relative mass of the isotope
A sample of bromine contains 53% of bromine-79 and 47% of bromine-81. Determine the relative atomic mass of bromine.
79.94 ( Go to page 9 for an example )
What is the relative mass and charge of a proton?
Relative mass = 1
Relative charge = -1
What is the relative mass and charge of a neutron?
Relative mass= 1
Relative charge = 0
What is the relative mass and charge of an electron?
Relative mass = 1/2000
Relative charge = - 1
Isotopes of the same element have?
- Different masses
- The same number of protons and electrons
- different numbers of neutrons in the nucleus.
What two numbers describe an element?
The atomic number(proton number)- the number of protons in the nucleus.
-The mass number(nucleon number) - the number of particles(protons and neutrons) in the nucleus.
How can you work out the number of neutrons an isotope has?
Subtract the mass number by the proton number.
For an isotope, relative isotopic mass=
atomic mass
When measuring atoms masses by comparing them to carbon-12, what assumptions have been made?
- We have neglected the tiny contribution that electrons make to the mass of an atom.
- We have taken the masses of both a proton and a neutron as 1.0u.
What does the weighted mean mass mean?
Most elements contain a mixture of isotopes, each in a different amount and with a different mass. We use the term “weighted mean mass” to account for the contribution made by each isotope to the overall mass of an element.
What does the contribution made by an isotope to the overall mass depend on?
- the percentage abundance of the isotope
- the relative mass of the isotope
