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Flashcards in Atomic Structure Deck (12)
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What is the atomic number

Number of protons


How is mass number calculated

Number of protons + number is neutrons


What is an isotope

Different forms of the same element
Same number of protons but different neutrons



1s2 2s2 2p6 3s2 3p6 4s2 3d10


Does 3d or 4s have a higher energy



What is an orbital

A region around the nucleus that can hold up to two electrons


Explain why chromium does not fit the trend for electron configuration

It only has one electron in its 4s orbital before filling 3d


Explain why cooper does not for the trend

It only has one electron in its 4s orbital before filling 3d


Two types of ionisation for a mass spec

1. Electron impact. Electron gun knocks off one electron from each particle to form 1+ ion

2. Electron spray. Sample dissolved in volatile solvent and injected through a fine needle which is attached to a positive terminal of a high voltage power supply and particles gain a proton from the solvent as they leave the needle


When would you use each type of ionisation in mass spec

Electron impact used with low formula mass

Electron spray used with high formula mass


How does time of flight mass spec work

Acceleration- positive ions towards a negatively charged plate
Ion drift- ion passes through a hole in plate, form a beam with constant energy, travel alone a tube to detector
Detection- positive ions pick up electrons, time of flight is recorded


Define first ionisation energy

The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions