1.1 Flashcards
define the atomic number
the number of protons in the nucleus of an atom of that element
define mass number
the sum of the nucleus of protons and neutrons in the nucleus if an atom
what are isotopes
atoms of the same element with different masses
what does a mass spectrometer do
measures the mass of atoms and molecules using a magnetic field
what is an M + 1 peak caused by
when the percentage of carbon-13 isotope becomes significant enough to be detected in large organic substances
define relative atomic mass
the weighted mean mass of an atom of an element compared to the 1/12 of the mass of an atom of carbon -12
define relative isotopic mass
the mass of an individual atom of a particular isotope relative to 1/12m of the mass of an atom of carbon-12
what is the molecular ion peak
the peak with the highest m/z ratio in the mass spectrum, the M peak z-charge
what is the shape of an ‘s’ orbital
spherical
what is the shape of a ‘p’ orbital
elongated dumbbell shape and a variable charge density
define a quantum shell
the energy level of an electron
define electronic configuration
shows the number of electrons in each sublevel in each energy level of the atom
define an orbital
a region within an atom that can hold up to two electrons with opposite spins
what’s hunds rule
states that electrons will occupy the orbitals singly before pairing takes place
what’s pauli exclusion principle
that two electrons cannot occupy the same orbital unless they have opposite spins
what happens when electrons move back to the lower energy level
they emit electromagnetic radiation
what’s the equation for first and second ionization energy
X(g) -> X+(g) + e-
X+(g) -> X2+(g) + e-
what are the 4 factors that affect ionization energy
the orbital an electron is in
the atomic radius
the shielding
the nuclear charge of an atom
explain the trend in ionization energy from hydrogen to helium
the increased nuclear charge makes it a lot harder to remove the electron as there is a stronger force of attraction, shielding is negligible
define first ionization energy
the energy required to remove an electron from each atom in one mole of atoms in the gaseous state
what is the trend in ionization energy between He and Li and why
first ionization of Li is lower than He as there is a new shell so increased shielding
why has Ne got a lower ionization energy than He
its easier to remove an electron from a p orbital as its got a higher energy level
define second ionization energy
the energy required to remove an electron from each singly charged positive ion in one mole of positive ions in the gaseous state
how do you measure the atomic radius
the distance between the center of two nuclei divided by 2
