Atomic Structure And Isotopes & Compounds, Formulae And Equations Flashcards
Which letter is used to represent the atomic number of an atom?
Z
Which letter represents the mass number?
A
Define isotope.
Atoms with the same number of protons but a different number of neutrons.
Why does different isotopes of the same element react in the same way? (2)
- Neutrons have no impact on the chemical reactivity
- Reactions involve electrons, isotopes have the same number of electrons in the same arrangement
What are ions.
Charged particles that are formed when an atom gains or loses electrons.
What is the unit used to measure atomic mass called?
Unified atomic mass unit, u.
Define relative atomic mass
The weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12
Define relative isotopic mass.
The mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon-12.
What two assumptions are made when calculating mass number?
- Contribution of the electron is neglected
- Mass of both proton and neutron is taken as 1.0 u
What are the uses of mass spectrometry?
- Identify unknown compounds
- find relative abundance of each isotope of an element
- determine structural information
How does a mass spectrometer work?
- the sample is made into positive ions.
- they pass through the apparatus and are separated according to mass to charge ratio
- a computer analyses the data and produces mass spectrum
How is the group number related to the number of electrons?
Group number = number of electrons in the outer shell.
Which are the 4 elements that don’t tend to form ions and why?
The elements are beryllium, boron, carbon and silicon
Requires a lot of energy to transfer outer shell electrons.
What are molecular ions?
Covalently bonded atoms that lose or gain electrons.
What is the charge of an ammonium ion?
NH4 (+)
