Module 2 - Atomic Structure and Isotopes , Compounds, formulae and equation
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What is the charge of a proton?
1+
What is the charge an electron?
1-
Which particle has the same mass as proton?
Neutron
Which two particles make up most of atom’s mass?
Protons and neutrons
Which letter is used to represent the atomic number of an atom?
Z
What does the atomic number tell about an element?
Atomic number = number of protons in an atom
Which letter represents the mass number?
A
How is mass number calculated?
Mass number = number of protons + number of neutrons
How to calculate the number of neutrons?
Number of neutrons = mass number - atomic number
Define isotope
Atoms of the same element with 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 is formed when an atom loses or gains electrons
What is the charge of the ion when electrons are gained?
Negative N.B - positive charge when electrons are lost E.g. 3+ ion has lost 3 electrons
What is the unit used to measure atomic masses 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
What is the unit of relative atomic mass?
No units
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
The relative isotopic mass is same as which number?
Mass number
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
How to calculate the relative molecular mass and relative formula mass?
Both can be calculated by adding the relative atomic masses of each of the atom making up the molecule or the formula
What are the uses of mass spectrometry? (3)
● 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
Does the group number indicates horizontal or vertical column in the periodic table?
Vertical column