Periodicity Flashcards
What does the Periodic Table arrange the known elements into?
Atomic (proton) number
What do all the elements along a period have the same number of?
Electron shells
What do all the elements down a group have the same number of?
Outer electrons
What does the stepped line divide?
Metals and Non Metals
What kind of properties do elements that touch the stepped line have? What are these elements known as?
Both metal and non metal properties. They are metalloids
What block is groups 1 and 2 in, on the periodic table?
S block
Why is group 1 and 2 in the s block?
All the elements have their highest energy electrons in the s-orbital
What block is groups 3 to 0 in, on the periodic table?
P block
Why is groups 3 to 0 in the p block?
The elements have their highest energy electrons in the p-orbital
Elements that have their highest energy electrons in the d-orbital are in which block?
d block
Why are the transition metals and d-block not exactly the same?
Scandium and Zinc aren’t transition metals as they don’t form compounds where they have partly filled d-orbitals
What block are the radioactive elements in, on the periodic table?
f block
Describe the reactivity of the s block elements
s block elements get more reactive going down the group
Describe the reactivity of the non metals
They get more reactive going up the group
Describe the reactivity of the d block elements
They are usually quite unreactive. This is where most useful elements are found
Describe the reactivity of the lanthanides and what do they form?
The lanthanides are rarely met. They form 3+ ions and have similar reactivity
Describe the reactivity of the actinides and what do they do?
Actinides are radioactive. They trace elements except for Thorium and Uranium
Does atomic radius increase or decrease going a long a period?
Decreases
Why does atomic radius decrease going along a period?
Due to an increased nuclear charge for the same number of electron shells.
The outer electrons are pulled closer to the nucleus as increased charge produces a greater attraction so decreases
Does atomic radius increase or decreasing going down a group?
Increases
Why does atomic radius increase going down a group?
With each increment down a group an electron shell is added each time.
This increases the distance between outer electrons and nucleus reducing power of attraction.
More shells increases shielding where the inner shells create a barrier that blocks forces.
Nuclear attraction reduced further, atomic radius increases
Why do melting points vary across period 3?
As they depend on the structure and the bonding of the element
What type of bonding do Na, Mg and Al have? Are these metals or non metals?
Na, Mg and Al are metals with metallic bonding
Does the melting point of Na, Mg and Al increase or decrease?
Increase
Why does the melting point of Na,Mg and Al increase going across period 3?
As their metallic bond gets stronger. This is due to increasing positive charge, increased delocalised electrons and decreasing atomic radii
Describe the structure of silicone in period 3?
It is macromolecular and tetrahedral. Strong covalent bonds links its atoms
Describe the melting point of silicone
A lot of energy is required to break the strong covalent bonds giving a high melting point
Describe the melting points for Phosphorus (P4), Sulphur (S8), and Chlorine (Cl2)
They are molecular. Their melting point depends on Van der Waal forces which are weak and easily broken. More atoms in a molecule mean greater VDW forces so the boiling point S>P>Cl
Describe the structure and bonding of Argon
Argon is monatomic so its VDW forces are very weak. Its a noble gas that exists as individual atoms with a full outer shell of electrons
Describe the melting point of Argon
The full outer shell of electrons makes the atom very stable so the melting point of argon is very low and it exists as a gas at room temperature
Across a period does ionisation energy increase or decrease? Why?
Increases because of the decreasing atomic radius and increasing nuclear charge means that the outer electrons are held more strongly and so more energy is required to remove the outer electron and ionise the atom
Does ionisation energy increase or decrease going down a group? Why?
Decreases as the nuclear attraction between the nucleus and outer electrons reduces and increasing amounts of shielding means less energy is required to remove the outer electron
