3A - The Periodic Table Flashcards Preview

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Flashcards in 3A - The Periodic Table Deck (32):

Trends across a period? (5)

-Nuclear charge increases
-Same shell, similar electron shielding 
-Nuclear attraction increases
-Atomic radium increases
-1st ionisation energy increases


Trends in first ionisation energy down a group? (4)

Decreases as you go down a group.


-Atomic radium increases

-More inner shells so sheilding increases

-Nuclear attraction on outer electrons decrease

-First ionisation energy decreases


How are elements in the periodic table arranged?

Elements in the periodic table are arraged in order of increasing atomic number


Proterties of elements in the same period? (3)


What do elements in the same period show? Why?

-Different number of electrons in the outer shell

-Different types of orbitals in the outer shell

-Outer electrons are in the same quantum shell


Elements in a period show a trend in physical and chemical properties because they have different electronic configurations.


Proterties of elements in the same group? (3)


What do elements in the same group show? Why?

-Same number of electrons in the outer shell

-Same types of orbitals in the outer shell

-Outer electrons in different quantum shells


Elements in the same group show similar physical and chemical properties because they have similar electronic configurations.




What is periodicity?

It's the regular pattern in properties of the elements across different periods


How is a subshell different to a oribital?

Subshell = collection of orbitals

Orbital = Only contains up to 2 electrons


Define first ionisation energy

The amount of energy required to remove one mole of electrons from one mole of a gaseous atoms to form one mole of gaseous ions


Equation for first ionisation:

1. Boron

2. Nitrogen

3. General equation (X)

1. B(g) → B-(g) + e-

2. N(g) → N3- + e-

3. X(g) → X- + e-


Indicate where the elements of period 1, 2 and 3 start

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Describe the general trend in first ionisation energy change across a period

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Increases as you go across the period


How does the first ionisation change down a group?

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Decreases because the number of protons in the element increase. This increases the nuclear charge of the element.


Why do the first ionisation energies drop sharply between the group 0 element of one period and to the group 1 element of the next period?

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You have to take out the electron from another energy level, there's more sheilding electrons.


4 factors that affect the value of ionisation energies?

Charge of nucleus

Sheilding electrons

Distance from nucleus

Nuclear attraction - A consequence of the other 3 factors


Explain the atomic structure for general trends in first ionisation energy:

1. Across a period

2. Down a group

1. As you move across the period, first ionisation energy increases.

Nuclear charge increases.

Sheilding electrons and distance from nucleus stays the same.


2. As you go down a group, first ionisation energy decreases.

Less nuclear attraction.

Distance from nucleus and sheilding electrons increase (this becomes the more important factor)


Group 2 metals reactions with:



Dilute acids

Metal + Oxygen → Metal oxide

2M(s) + O2(g) → 2MO(s)


Metal + Water → Metal hydroxide + Hydrogen

M(s) + 2H2O(l) → M(OH)2(aq) + H2(g)


Metal + Acid → Salt + Water 


Group 2 Metal oxide + Water → ?


pH of solution formed when group 2 Metal oxide + water?

Metal oxide + water → Metal hydroxide


Solutions formed are metal hydroxides which are alkaline

pH = approx 10-12


List 3 different types of periodicity between period 2 and 3

Melting point and boiling point 

Electrical conductivity

Atomic radius


7 rules when assigning oxidation numbers

1. Uncombined elements = 0

2. Elements in simple ions has the same oxidaiton number as the charge on the ion e.g. I- = -1

3. Fluorine = -1

4. Oxygen = -2 (except in a peroxide then it's -1)

5. Hydrogen = +1 (except in hydride then it's -1)

6. Group 1 metal = +1

7. Group 2 metal = +2


Reactivity trends of group 1 and group 2 metals?

Group 1 metals = More reactive as you go down the group.

Group 2 metals = More reactive as you go up the group.


Give the 1st and 2nd ionisation energy equation of calcium 

1st: Ca(g) → Ca+(g) + e-

2nd: Ca+(g) → Ca2+(g) + e-


Describe the trend in solubility of the group 2 metal hydroxides as you move down the group

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Solubility increases as you go down the group. The strength of the electrostatic force of attraction between the OH- ions and the metal ions decrease as you go down the group


How is the solubility of the metal hydroxides related to their alkalinity?

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As solubility increases the alkalinity increases. 

If the metal hydroxide is more alkaline it's more likely to relase the OH- ions.


For Chlorine, bromine and iodine:

-State at RTP

-Appearance at RTP

-Associated hazards



-Green gas

-Poisonous by inhalation as it forms HCl in lungs




-Brown liquid (with orange vapour)

-Toxic, corrosive. 





-Toxic vapour when heated



What type of attraction exist between halogen molecules?

London forces - Caused by the fluctuations in the distribution of electrons which will cause an instantaneous dipole.


They can't have a permanent dipole as the 2 molecules are similar in electronegativity. 



What colour is Cl2,Br2 and I2 in water and in hexane?


What about Cl-,Br- and I-?

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When an organic solvent such as hexane is added to a solution containing halogens 2 layers form.


Explain, with reference to intermolecular forces, why 2 layers form.

The hexane is non-polar, it only forms London forces between molecules.

Water is polar and forms hydrogen bonds between molecules. 

The layers are immiscible (do not mix) as a polar substance won't dissolve a non-polar substance.


When an organic solvent such as hexane is added to a solution containing halogens 2 layers form.


Explain why adding the organic solvent is necessary to allow proper identification of the halogens in solution.

They'll all look the same in water alone.


Halogens are held together by london forces. They're favour in dossolving into the hexane than the polar solution of water.

This means that only the hexane will have a colour change.


Define disproportionation

The reaction in which the same element is both oxidised and reduced


Chlorine + water → ?

Chlorine + cold, dilute NaOH → ?

Chlorine + Water → Chloric (I) acid + Hydroden chloride

Cl2(g) + H2O(l) → HClO(aq) + HCl(aq)


Chlorine + cold, dilute NaOH → Sodium chlorate (I) + Sodium hydroxide + Water

Cl2(g) + 2NaOH(aq) → NaClO(aq) + NaCl(aq) + H2O(l)


Use of Sodium chlorate (I) - NaClO?

Household bleach


Suggest why sodium chlorate (I) is more effective as a bleach than chloric (I) acid?


Sodium clorate (I) fully dissociates where as chloric (I) acid only partially dissociates