Chemistry electron structure
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- Created by: I.m
- Created on: 28-12-12 01:20
When an atom loses an electron what does it become?
When an atom loses an electron it becomes a positive ion (cation) and is said to have been ionised.
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Define first ionisation energy.
The first ionisation energy of an element is the energy required to remove one electron from each atom in 1 mole of gaseous atoms to form one mole of gaseous 1+ ions.
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Define successive ionisation energy.
Successive ionisation energy is a measure of the energy required to remove each electron in turn.
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Give the first, second and third ionisation energies of K.
1st IE: K(g) = K+ (g) + e-. 2ND IE: K+ (g) = K2+ (g) + e-. 3RD IE: K2+ (g) = K3= (g) + e-.
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Explain the pattern in successive ionisation energies.
1. IE incrs in the order 1st, 2nd, 3rdetc.As each e- is remved frm an atom,the remaining ion becms moe pos charged so the attrction btwn the nuc+ outer e-s incrs threfre it becms mor difficult i.e.mor energy is required to remve the next e- each time
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What can be predicted if the number of electrons in the outer shell is known?
Group number can be predicted if the number of electrons in the outer shell is known.
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How else can group number be predicted without knowing the number of electrons in the outer shell?
Group number can be predicted using the first large jump in IE. This jump determines the number of outer shell electrons as it shows when the outer shell has been emptied as the next would be removed from a new shell closer to the nucleus.
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What 3 factors affect ionisation energy?
Atomic radius/distance, nuclear charge and shielding.
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How does atomic radius/distance affect ionisation energy?
Increasing the atomic radius increases the distance between the nucleus and outer shell electrons. This decreases the attractive force, therefore IE decreases.
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How does nuclear charge affect ionisation energy?
Increasing the number of protons in the nucleus increases the attractive force, therefore IE increases.
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How does shielding affect ionisation energy?
E-s in filled inner shells repel e-s in the outer shel +reduce the effect of the positive nuc charge.An increasing number of inner shell e-s therfre incrs shielding. The overall attractive force experienced by the outer e-s decrs threfre IE decrease
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Explain the trend in 1st ionisation energy (example Li).
Low 1st IE. Suggests 1 electron in the outer shell (n=2). This has the lowest IE as it is furthest from the nucleus and so is easiest to remove. This outer electron experiences a shielding effect from the two inner electrons.
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Explain the trend in 2nd ionisation energy (example Li).
Much larger 2nd IE. The very large increase in IE indicates the outer shell has been removed and the 2nd electron is being removed from a different shell closer to the nucleus (n=1). The elcytron is also ahrder to remove as it is being removed from a
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Explain the trend in 3rd ionisation energy (example Li).
Even large 3rd IE as the final electron is being removed from the inner shell of a 2+ ion. It is the hardest to remove so requires most energy to overcome the increased attraction from the nucleus.
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What does this confirm as simplified electronic structure of lithium?
This confirms the simplified electronic structure of lithium as 2.1
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What can successive ionisation be used to predict?
Successive IE can help predict the number of shells and the number of electrons in each shell.
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What are the labels of the x and y axis in a graph that shows successive IE trends
IE against the y axis and the number of electrons removed on the x axis.
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Why are log graphs sometime used to show IE?
Log graphs are often used to cope with large ranges for the ionisation energies.
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Give the number of electrons that can fit in the shells n=1,2,3 and 4.
n=1 2electrons can fit, n=2 8electrons can fit, n=3 18 electrons can fit and n=4 32electrons can fit.
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What are principal quantum numbers?
The energy levels or shells that are referred to using number n=1,2,3,4 etc.
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What do shells/energy levels consist of?
Shells consist of sub-shells.
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What do sub-shells consist of?
Sub-shells consist of orbitals.
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Define an orbital.
An orbital is a region within an atom that can hold up to two electrons (with opposite spins).
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Which way can spins be rotating?
Spins can either be rotating clockwise or anticlockwise.
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If an orbital is filled with two electrons what must the spins be?
If an orbital is filled with two electrons, they must have opposite spins.
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What is the shape of an s orbital?
S orbitals are spherical.
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What is the shape of a p orbital?
P orbitals are dumb-bell shaped.
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What are subshells made up of?
Subshells are made up from different numbers and types of orbitals.
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What does an s sub-shell consist of?
An s sub-shell a single s orbital.
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What does a p sub-shell consist of?
A p sub-shell consists of three p orbitals.
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What does a d sub-shell consist of?
A d sub-shell consists of five d orbitals.
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What does an f sub-shell consist of?
An f sub-shell consists of seven orbitals.
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How are electrons added to orbitals and which is filled first?
Electrons are added one at a time; orbitals of lowest energy are filled first.
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What must each energy level be before the next higher level begins to fill?
Each energy level must be full before the next, high level, begins to fill.
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Give the electron configuration of the order of orbitals that are filled.
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶.
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1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶. What is the highest electron configuration for atoms and some ions can this electron configuration be used for?
This electron configuration can be used for atoms/ions up to atomic number=36.
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What must be done to the electron configuration of positive ions?
Positive ions – electrons are removed from the highest energy orbitals (electron configuration decreases).
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What must be done to the electron configuration of negative ions?
Negative ions – electrons are added to the highest energy orbitals (electron configuration increases).
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What are the 3 block in the periodic table?
S block, d block and p block.
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What does the block of an element correspond to?
The block in which any given element is found corresponds to the highest occupied sub-shell/orbital within that element.
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Other cards in this set
Card 2
Front
Define first ionisation energy.
Back
The first ionisation energy of an element is the energy required to remove one electron from each atom in 1 mole of gaseous atoms to form one mole of gaseous 1+ ions.
Card 3
Front
Define successive ionisation energy.
Back
Card 4
Front
Give the first, second and third ionisation energies of K.
Back
Card 5
Front
Explain the pattern in successive ionisation energies.
Back
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