4592413
Descripción
Fichas por Michelle Browne, actualizado hace más de 1 año
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Creado por Michelle Browne
hace casi 9 años
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| Pregunta | Respuesta |
| What is an isotope? | Atoms with the same number of protons but a different number of neutrons. |
| What are the principles of the Bohr model? | -Electrons can only exist in fixed shells. -Each shell has a fixed energy. -Radiation is emitted or absorbed when electons move between shells. -The radiation has a fixed frequency because the energy of the shells is fixed. |
| What is relative atomic mass? | The average mass of an atom of an element on a scale where an atom of carbon-12 is 12. |
| What is relative isotopic mass? | The mass of an atom of an isotope of an element on a scale where an atom of carbon-12 is 12. |
| What is relative molecular mass? | The average mass of a molecule on a scale where an atom of carbon-12 is 12. |
| What are the 5 stages in mass spectroscopy? | 1. Vaporisation 2. Ionisation 3. Acceleration 4. Deflection 5. Detection |
| What is vaporisation? | The sample is turned into gas using an electrical heater. |
| What is ionisation? | -The gas particles are bombarded with high-energy electrons to ionise them. -Electrons are knocked off the particles leaving positive ions. |
| What is acceleration? | The positive ions are accelerated by an electric field. |
| What is deflection? | -The positive ions paths are altered with a magnetic field. -Lighter ions have less momentum and are deflected more than heavier ions. -Only ions with a particular m/z ratio make it to the detector. |
| What is detection? | -The magnetic field strength is slowly increased. -Ions with a higher m/z ratio reach the detector first. -A mass spectrum is produced. |
| What are 2 exceptions in electron configuration? | Chromium (Cr) and copper (Cu). |
| Why are they exceptions? | They donate one of their 4s electrons to the 3d sub-shell. |
| What is the 1st ionisation energy? | The energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ atoms |
| What are 3 factors affecting ionisation energy? | -Nuclear charge -Distance from nucleus -Shielding |
| How does nuclear charge affect ionisation energy? | The more protons there are in the nucleus, the more positively charged the nucleus is and the stronger the attraction for the electrons. |
| How does the distance from the nucleus affect ionisation energy? | -Attraction falls off very rapidly with distance. -An electron close to the nucleus will be much more strongly attracted than one further away. |
| How does shielding affect ionisation energy? | -The higher the number of electrons between the nucleus and outer electrons, the less attraction there is towards the nuclear charge. |
| What is the trend for ionisation energy down group 2? | Ionisation energy decreases as the extra sheilding counteracts the increased nuclear charge. |
| What is the rrend for ionisation energy across a period? | Ionisation energy increases because of the increasing number of protons means a stronger nuclear attraction. |
| What is the drop caused by between groups 2 and 3? | Aluminium's outer electron is in a 3p orbital rather than a 3s. |
| What is the drop between groups 5 and 6 caused by? | -In sulfur the electron is being removed from an orbital containing 2 electrons. -This electron repulsion means the electrons are easier to remove. |
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