3.1.1: Periodicity Flashcards

1
Q

How are the elements arranged in a periodic table?

A

They are arranged in the order of

increasing atomic numbers

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2
Q

What is a period on a periodic table?

A

The horizontal rows in the periodic table

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3
Q

What is a group on a periodic table?

A

The vertical columns

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4
Q

What is meant by periodicity?

A

The repeating trends in chemical and

physical properties

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5
Q

What change happens across each period?

A

Elements change from metals to non metals

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6
Q

How can the electron configuration be written in short?

A

The noble gas before the element is
used to abbreviate
E.g Li → 1s2
2s1 ; Li → [He] 2s1

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7
Q

Define first ionisation energy

A

The energy required to remove one electron from each atom in one mole of the gaseous element to form one mole of gaseous 1+ ions

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8
Q

Write an equation for the first ionisation energy of magnesium

A

Mg (g) → Mg+ (g) + e

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9
Q

What are the factors that affect ionisation energy?

A

● Atomic radius
● Nuclear charge
● Electron shielding or screening

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10
Q

Why does first ionisation energy increases across period 3?

A

-Increased nuclear charge
-Decreased atomic radius
-Same electron shielding which means more energy is needed to remove the first electron.
Dips at Al because: outer electron is in a 3p orbital, higher energy than 3s orbital → less energy needed to remove electron
Dips at S because one 3p orbital contains two electrons → repulsion between paired electrons → less energy needed to remove one

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11
Q

Why does first ionisation energy decrease between group 2 to 3 ?

A

● Decrease between 2 to 3 because in group 3 the outermost electrons are in p orbitals whereas in group 2 they are in s orbital, so the electrons are easier to be removed

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12
Q

Why does first ionisation energy decrease between group 5 to 6?

A

The decrease between 5 to 6 is due to the group 5 electrons in p orbital are single electrons and in group 6 the outermost electrons are spin paired, with some repulsion. Therefore the electrons are slightly easier to remove

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13
Q

Does first ionisation increase or decrease between the end of one
period and the start of next? Why?

A

Decrease
● There is increase in atomic radius
● Increase in electron shielding

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14
Q

Does first ionisation increase or decrease down a group? Why?

A

● Decrease
● Shielding increases → weaker attraction
● Atomic radius increases → distance between the outer
electrons and nucleus increases → weaker attraction
● Increase in number of protons is outweighed by increase
in distance and shielding

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15
Q

What are the properties of giant metallic lattices? (4 marks)

A

● High melting and boiling point
● Good electrical conductors
● Malleability
● Ductility

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16
Q

What is a ductile metal?

A

The metal can be made stretched. E.g

Can be made into wires

17
Q

What is a malleable metal mean?

A

The metal can be shaped into different

forms

18
Q

Describe the structure, forces and bonding in every element across period 2

A

● Li & Be → giant metallic ; strong attraction between
positive ions and delocalised electrons ; metallic bonding
● B & C → giant covalent ; strong forces between atoms ;
covalent
● N2, O2, F2, Ne → simple molecular ; weak intermolecular forces between molecules ; covalent bonding within molecules and intermolecular forces between molecules

19
Q

Describe the structure, forces and bonding in every element across period 3

A

● Na, Mg, Al → giant metallic ; strong attraction between
positive ions and delocalised electrons ; metallic bonding
● Si → giant covalent ; strong forces between atoms ;
covalent
● P4, S8, Cl2, Ar → simple molecular ; weak intermolecular forces between molecules ; covalent bonding within molecules and intermolecular forces between molecules