2.1.1. Atomic Structure And Isotopes Flashcards
What defines the atomic number of an element?
The atomic number is the number of protons in the nucleus of an atom.
How do you determine the number of neutrons in an atom?
The number of neutrons is calculated by subtracting the atomic number from the mass number (mass number - atomic number).
What is the charge of an ion if it has more electrons than protons?
The ion is negatively charged.
What does the Bohr model explain in terms of atomic structure?
An atom has a small, positively charged central nucleus and electrons orbiting in at specific fixed distances from the nucleus.
How has the accepted model of atomic structure changed over time?
The model for atomic structure has evolved over time as knowledge and scientific understanding changes. The current, accepted model of the atom consists of a small, dense central nucleus surrounded by orbiting electrons in electron shells. This was discovered in the Rutherford scattering experiment in 1911.
What is relative isotopic mass?
Relative isotopic mass is the mass of an isotope compared to 1/12th the mass of a carbon-12 atom.
Define relative atomic mass.
Relative atomic mass is the weighted mean mass of an atom compared to 1/12th the mass of a carbon-12 atom.
How is mass spectrometry used to determine relative isotopic masses?
Mass spectrometry measures the mass-to-charge ratio of ions, allowing the determination of isotopic masses and their relative abundances.
How can the relative atomic mass of an element be calculated from isotopes?
Relative atomic mass can be calculated by taking the weighted average of the isotopic masses based on their relative abundances.
What is the difference between relative molecular mass and relative formula mass?
Relative molecular mass (Mr) is used for simple molecules e.g. H2O, CO2, while relative formula mass is used for compounds with giant structures e.g. diamond, graphite.
What are isotopes?
Isotopes are atoms of the same element that have different numbers of neutrons and, consequently, different masses.
What evidence led to the rejection of the Thomson model of the atom?
Rutherford’s gold foil experiment provided evidence for a small, dense nucleus, leading to the rejection of the Thomson plum pudding model.
What is the difference between an shell, subshell and an orbital?
Shell - The fixed energy level an electron is in
Subshell - Within a shell - S, P, D, F
Orbital - Within subshell - Carry two electrons which will experience opposite sspiin
