Karteikarten
Atomic structure
Karten in diesem Stapel (24)
- 1What is the relative mass, charge and location (in the atom) for protons, neutrons and electrons?Protons- 1,+1, inside nucleus
Neutrons- 1,0, inside nucleus
Electron- 1/1840, -1, in energy levels - 2Define isotopeAtoms of the same element which have the same number of protons and electrons but different numbers of neutrons (and therefore different masses)
- 3Do isotopes have the same chemical and physical properties?They have the same chemical (due to the same number of electrons) but different physical properties (due to different masses)
- 4Define relative isotopic massThe mass of a single isotope of an element relative to 1/12 the mass of an atom of carbon-12
- 5Define relative atomic massThe weighted average mass of an atom of an element relative to 1/12 the mass of an atom of carbon-12
- 6Define relative molecular massThe mass of a molecule relative to 1/12 the mass of an atom of carbon-12
- 7What is the purpose of mass spectrometry? (6)-Determine relative isotopic masses and their relative abundance
-Used to calculate the Mr
-Identify unknown purified compounds
-Quality control in pharmaceutical industry
-Testing for drug abuse
-Carbon dating - 8What happens to the solvent before it is put into the process of time of flight?The sample is first dissolved in a polar, volatile solvent and pumped through a narrow capillary tube to create droplets of the solution.
A polar volatile solvent is used to ensure that the solution evaporates. - 9Describe the process of time-of-flight mass spectrometer1) Electrospray ionisation: A high voltage is applied to the tip of the capillary tube to form highly charged droplets. These droplets evaporate to form gaseous charged ions that are positively mononuclear.
2) Acceleration: An electric field is applied to give all the ions the same kinetic energy. As the ions have different masses but the same kinetic energy, heavier ions move slower than the lighter ions.
3) Ion drift: The ions enter a region with no electric field called the flight tube. They are separated based on their different velocities. The smaller fast ions travel through the tube more rapidly and arrive at the detector first.
4) Ion detection: The detector (a negatively charged plate) records the different flight times. The positive charged ions arrive at the detector and cause a small electric current (due to their charge)
5) Data analysis: The flight times are analysed and recorded as a mass spectrum by the data analyser. The mass spectrum is a plot of the relative abundance against the mass-to-charge ratio (m/z). - 10What is the molecular ionThe last major peak with the highest m/z value. It is the Mr of the compound
- 11What is the process of fragmentationWhen a molecule is put through mass spectrometer and the molecule breaks up.
- 12What is the base peakThe peak with the greatest abundance
- 13What is the (full) electronic configuration for chromium and copper?Chromium-1s2 2s2 2p6 3s2 3p6 3d5 4s1
Copper-- 1s1 2s2 2p6 3s2 3p6 3d10 4s1 - 14Define isoelectronicParticles that have the same electronic configuration.
Example: a neon atom and oxide ion - 15What is ionisationThe process of removing electrons from atoms and ions
- 16Define ionisation energyThe energy required to remove 1 mole of gaseous electrons from 1 mole of gaseous atoms, to form 1 mole of gaseous 1+ ions.
- 17Why is there a general increase in successive ionisation energies?As the number of electrons removed increases, the effective nuclear charge increases. This results in a greater attraction of electrons to the nucleus
- 18How can the existence of energy levels be proven by ionisation energy graphs?Large gaps between ionisation energies indicate an energy level. This is because as an energy level is removed, the electrons are closer to the nucleus so more energy is needed to remove the electron.
- 19What are the 3 factors that affect patterns in ionisation energies?-Atomic radius
-Nuclear charge
-Shielding - 20Why does the first ionisation energy decrease down a group?-The atomic radius increases therefore outer electrons feel a weaker attraction to the nucleus
-Shielding increases because as you go down a group, you add another shell. This also decreases the strength of attraction
-Although the nuclear charge increases, shielding and the increased atomic radius play a greater role - 21Why does the first ionisation energy increase across a period?-The atomic radius decreases as you go across a period, therefore the outer electrons are closer to the nucleus and feel a greater attraction.
-Shielding does not play a role as the outer electron removed is from the same energy level.
-Nuclear charge increases - 22Which group has the lowest and highest first ionisation energy? Why?Lowest- Group 1 elements as they have the largest atomic radius but the lowest nuclear charge (in a period)
Highest- Group 0 as they have the smallest atomic radius but the highest nuclear charge (in a period) - 23Why are there lower first ionisation energies than expected for Group 3 and 6 elements?Group 3 have a s2 p1 arrangement therefore the outer p1 electron is furthest from the nucleus. The inner s2 electrons increase shielding which reduces the energy needed to ionise the first outer electron
Group 6 have a p4 arrangement. The repulsion of 2 electrons in the same p orbital leads to less energy needed to ionise the outer shell. - 24Which group has the highest SECOND ionisation energy?Group 1 (as it has a full outer shell and the effective nuclear charge will be larger causing a greater attraction)
Informationen
- Beschreibung
- AS - Level Chemistry (1. Atomic structure) Karteikarten am Atomic structure, erstellt von Dolu Falowo am 27/10/2015.
- Erstellt von
- Dolu Falowo · Okt 2015
- Aktualisiert
- 5 Jan 2017
- Aufrufe
- 0
- Bewertung