atomic structure p1 Flashcards
explain the current model of the atom
- protons and neutrons are found in the nucleus
- electrons orbit the nucleus in shells
- the nucleus is tiny compared to the total volume of atom
- most of atom’s mass is in the nucleus
- most of the atom is empty space between the nucleus and the electrons
what is the charge of a proton and an electron?
proton = +1
electron = -1
which particle has the same mass as proton?
neutron
which two particles make up most of atom’s mass?
protons and neutrons
what does the atomic number show about an element?
atomic number = number of protons in an atom
how is the mass number calculated?
mass number = number of protons + number of neutrons
isotope
atoms of the same element with different number of neutrons and therefore different mass number
why do different isotopes of the same element react in the same way?
- neutrons have no impact on the chemical reactivity
- reactions involve electrons, isotopes have the same number of electrons in the same arrangement
relative atomic mass
weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12
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
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?
- identify unknown compounds
- find relative abundance of each isotope of an element
- determine structural information
what is the m/z value of the M+ ion from a graph??
last peak
what does the principal quantum number indicate?
the shell occupied by the electrons