CHAPTER 7 PERIODIC TABLE & ENERGY Flashcards
What is the first ionisation energy?
The first ionisation energy is the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.
How do you display first ionisation energy?
Na(g) —> Na+(g) + e-
What are the three factors that affect the attraction between the nucleus and outermost electrons?
atomic radius, nuclear charge and electron shielding.
What happens across a period?
- The atomic radius decreases
- The nuclear charge increases
- Shielding remains the same
What is periodicity?
A repeating trend in properties (of elements)
How is the periodic table divided into blocks?
Group 1-2 = s-block
Group 3-12= d-block
Group 13-18= p-block
Period 6-7= f-block
What are groups?
Elements with similar outer shell electron structures resulting in similar properties.
What are the electron configurations for the noble gases?
Helium = 2 Neon = 10 Argon = 18 Krypton = 36
What happens to the first electrons lost?
It comes from the highest energy level and experiences the least attraction from the nucleus.
How many ionisation energies are there?
As many electrons are there eg helium has two electrons so it has 2 ionisation energies
Why is the second ionisation energy stronger than the first?
Because, after the first electron is lost, the electrons are pulled closer to the nucleus so the nuclear atrraction increases and more ionisation energy will be needed to remove the next electron.
What is the second ionisation energy?
The amount of energy required to remove an electron from each ion in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions.
What dramatically increases the ionisation energy of an element?
The difference of shells. Eg the ionisation energy between a 2p and 3s would be dramatic compared to 3s and 3p.
What are factors effecting ionisation energies?
- Nuclear charge (The greater the nuclear charge the more ionisation energy needed)
- Shielding ( The more electron shields the lower the ionisation energy)
- Atomic radius ( The larger the atomic radius the lower ionisation energy needed)
What is the difference between ionisation energy in groups and periods?
In periods the ionisation energy increases, in groups the ionisation energy decreases.
What is the trend in ionisation energy down a group?
- Atomic radius increases
- Shielding increases
- Nuclear charge decreases
What are state symbols?
Symbols to state the state of matter the element is in eg g for gas
Why does Al have a lower first ionisation energy than Mg?
Because the paired electrons in the … subshell repel each other making it easier to remove an electron from Al than Mg therefore lowering the ionisation energy
What happens with room temperature and metals?
Metals become solid.
What is metallic bonding?
Metallic bonding is the strong electrostatic attraction between cations and delocalised electrons.
What is the structure in metallic bonding?
- Cations are in a fixed position maintaining the structure and shape of the metal
- Delocalised electrons are mobile and able to move throughout the structure
What is the structure of a metallicly bonded element called?
Giant metallic lattice
What is a lattice ?
A lattice is a structure with a regular pattern of oppositely charged ions.
What are the properties of metals?
- Strong metallic bonds
- High electrical conductivity
- High melting and boiling points
