Karteikarten
Atomic Structure and Periodicity
Karten in diesem Stapel (48)
- 1What did Robert Boyle discover?there were some substances that could not be made simpler
- 2What did John Dalton discover?elements were composed of indivisible atoms. All atoms of a particular element had the same mass and atoms of different elements had different masses. Atoms could not be broken down
- 3What did Henri Becquerel discover?radioactivity. This showed that particles could come from inside the atom
- 4What did JJ Thomson discover?discovered the electron. He showed that electrons were negatively charged and electrons from all elements. Plum pudding model.
- 5What did Ernest Rutherford discover?most of the mass and all the positive charge of the atom was in the nucleus
- 6What did Neils Bohr discover?the atom consists of a tiny positive nucleus orbited by negatively charged electrons. Quantum Theory.
- 7What did Erwin Schrodinger discover?worked out an equation that used the idea that electrons had some of the properties of waves as well as those of particles
- 8What did James Chadwick discover?the neutron
- 9What are the symbols of protons, electrons and neutron?P, e- and N
- 10What are the relative masses of protons, electrons and neutron?1 amu, 1/1840 and 1 amu
- 11What are the relative charges of protons, electrons and neutron?+, - and neutral
- 12What are the locations of protons, electrons and neutron?in the nucleus, orbiting around the nucleus and in the nucleus
- 13What is an isotope?Isotopes are variants of a particular chemical element which differ in neutron number
- 14Why do scientists use relative atomic mass and how?Atoms are very small so instead of using metric scale to measure them, scientists compare their masses to the standard, carbon-12. On this relative scale, carbon-12 has a mass of exactly 12.
- 15What is relative atomic mass?the weighted average mass of an atom of an element, compared to 1/12 of the mass of an atom of carbon-12, which has a mass of 12.
- 16What is relative isotopic mass?the mass of an atom of an isotope, compared to 1/12 of the mass of an atom of carbon-12, which has a mass of 12.
- 17What is first ionisation energy?The energy required to remove one mole of electrons from one mole of atoms of the element in the gaseous state to form gaseous ions
- 18What are quantum mechanics?the electrons are always moving
- 19What is ground state?the lowest energy for an atom
- 20What are valence electrons and what do they do?the outer most electrons with highest energy, they determine chemical properties and are molest likely in bond formation or ionisation
- 21Why is the outermost electron the lowest ionisation energy?It needs the least amount of energy to remove e- because it is the highest quantum level (has shielding by repulsion from non-valence e-) and is furthest from the nucleus
- 22Why do successive ionisation energies increase?As each electron is removed, the same number of protons attract fewer electrons, it is more difficult to remove an electron from an increasingly positive ion
- 23What do big jumps in successive ionisation energies usually indicate?Removing electrons from inner shell electrons
- 24How do you deduce the group elements are from by a list of their successive ionisation energies?Find the big jumps, the number of IEs before the jump are the number of electrons in the outer shell and therefore the group
- 25How do you deduce the second ionisation energy?The second ionisation energy of an element is always the same as the first ionisation energy of the element before it
- 26What is the trend in IE across a period and why?It increases because more energy needed to remove electron. Same quantum shell, shielding factors and distance but charge gets higher as electron is removed each time. Increasing protons and charge so stronger force each time.
- 27What is the trend in IE down a group and why?It decreases because every group has a new shell. Outer electron progressively removed from a quantum shell that is further from the nucleus each time, weaker force of attraction. Shielding provided by non-valence e- so less energy needed to remove outer e-.
- 28Why are there uncharacteristic drops between Be to B and Mg to AlP subshell electrons are at a slightly higher energy than those in the s subshell, so they take less energy to remove. Nuclear charge isn’t enough to overcome the difference in s and p subshells.
- 29Why are there uncharacteristic drops between N to O and P to SThe outer electron is in an orbital with another electron with opposite spin so it is experiencing a force of repulsion and is therefore easier to remove.
- 30What is periodicity?a repeating pattern that is observed across the Periodic Table in successive periods
- 31What are the trends in atomic radii and why?Decreases across a period, Increases down a group
Bigger nuclear charge attracts electrons in the same quantum shell, pulling them more closely into the nucleus - 32How many orbitals are in each sub shell/• The s sub-shell comprises 1 orbital
• The p sub-shell comprises 3 orbitals
• The d sub-shell comprises 5 orbitals
• The f sub-shell comprises 7 orbitals - 33How many electrons can each orbital hold?Each orbital can only hold 2 electrons. Once you reach max of 2, you have to make a new orbital in that sub shell, until you reach the max of orbitals that sub shell can make (1 for s)/ electrons that can go in that sub-shell (2 for s) then you go to the next letter.
- 34What shape are s and p subshells?S is a spherical cloud and P is a dumbshell shape
- 35What is Aufbau principle?Fill orbitals of lowest energy first
- 36What is Pauli Exclusion Principle?Two electrons in the same orbital have opposite spin
- 37What is Hunds rule?Electron goes into an empty orbital before pairing up
- 38What does mass spectrometry show us?the masses of the ions detected and their relative abundance i.e. the isotopic composition of an element
- 39What are the four main stages of mass spectrometry?Ionisation, acceleration, deflection and detection
- 40What are the two types of ionisation?electron impact and electrospray ionisation
- 41Describe electron impact ionisationsample is vaporised, and high energy electrons are fired at it, usually knocks off one electron from each particle, forming a 1+ ion. Used for low formula mass substances
- 42Describe electrospray ionisation?sample is dissolved in a volatile solvent and the injected through a hollow needle to give fine mist. This is connected to the +ve voltage supply. This produces positive droplets which have lost electrons. The solvent evaporates creating single positively charged ions.
- 43Describe the acceleration processThe positive ions are attracted towards a negative electric plate which causes the ions to accelerate towards the plate so that all ions have the same kinetic energy
The larger, heavier particles will have a lower speed - 44Describe the deflection processThe ions pass through a hole in the negatively charged plate- this forms a beam . The beam of ions travel along a tube- this is a flight tube
- 45Describe the detection processWhen the ions arrive at the detector, their flight times are recorded. At the detector, the positive ions pick up and electron- this causes a current to flow. The detector passes a signal to the computer which generates a mass spectrum
- 46How is the time of flight calculated?Positive ion travel through a hole in the negatively charged plate into a tube. The time of flight of each particle through this flight tube depends on its velocity that in turn depends on its mass
- 47What are the main equations concerning time of flight?time of flight = distance/ velocity
KE = 1/2 m v(squared) - 48How do you get the mass of an ion?You will be given the mass of the ions in g so you will need to convert them into kg. To do that, you must divide by Avogadro’s number to find the mass of one ion and then divide by 100 to convert to kg.
Informationen
- Beschreibung
- A level Chemistry (PHYSICAL CHEMISTRY) Karteikarten am Atomic Structure and Periodicity, erstellt von Aafreen Butt am 25/09/2020.
- Erstellt von
- Aafreen Butt
- Aufrufe
- 0
- Bewertung