Atomic Number Flashcards
What three words describe the nucleus?
Small, dense, central
What is the nucleus surrounded by?
Orbiting electrons in electron shells
Why does the nucleus have an overall positive charge?
Consists of protons and neutrons
Where is the mass of the atom concentrated?
The nucleus
What are the relative numbers of protons and electrons in a neutral atom?
Same number of protons and electrons
What is the relative mass of a neutron?
1
What is the relative mass of an electron?
1/1840
What is the relative mass of a neutron?
1
What is the formula for calculating the maximum number of orbiting electrons than can be held by a single shell?
2n2
What is the mass number?
The sum of protons and neutrons in an atom
What is the atomic number?
The number of protons in an atom (also known as the proton number)
How are ions formed?
When an atom gains or loses electrons
Why does an ion have an overall charge?
It has lost or gained electrons so the charges of protons to electrons no longer cancel our
What is an isotope?
Atoms of the same element with the same atomic number, but with a different number of neutrons resulting in a different mass number.
Why do neutral atoms of isotopes react CHEMICALLY the same way?
They have the same proton number and the same electron configuration
In isotopes, is the sharing and transfer of electrons affected?
No
Do isotopes have different physical properties?
Yss
What is relative atomic mass?
A weighted mean, average mass of an atom of an element relative to 1/12th of the main mass of an atom of the carbon-12 isotope.
What is the formula for working out Ar?
Mean mass of an atom of an element / 1/12 x mean mass of C-12 isotope
What is relative isotopic mass?
The isotopic mass of an isotope relative to 1/12 of the mean mass of an atom of carbon 12 isotope
What Is the relative molecular mass?
The weighted, mean, average mass of a molecule of a compound relative to 1/12 of the main mass of an atom of the carbon-12 isotope
How can relative molecular mass be calculated?
By adding together the separate Ar values of the component elements.
When is relative formula mass used?
For compounds with giant structures
What is Mass Spectrometry used for?
To identify different isotopes and find the overall relative atomic mass of an element.
