Periodic table Flashcards
What is a group in the periodic table?
A column of elements with similar properties and the same number of outer shell electrons
What is a period in the periodic table?
A horizontal row. Elements show trends in properties across a period.
What is periodicity?
The regular repeating pattern in properties of the elements across different periods
How is a subshell different from an orbital?
A subshell is a group of the same type of orbitals.
Orbitals are regions of an atom containing up to 2 electrons with opposite spins. (s orbitals are spherical in shape, p orbitals are dumbbell shaped.)
How many electrons can an orbital hold?
2
Which has a higher energy level, an N d orbital or an N+1 s orbital
The d orbital
How are noble gas electron configurations shown
[Noble Gas} Then electron config from that level
What is first ionisation energy?
The energy required to remove one electron from each atom in one mole of gaseous atoms (to form 1 mole of gaseous 1+ ions)
What is the first i.e. equation of any element, X?
X(g) —> X+(g) + e-
What is the general trend in first i.e. across a period?
Increases
How does first ionisation energy change down a group?
Decreases
Why do the first ionisation energies drop sharply between the Group 0 element of one period to the Group 1 element of the next period?
The electrons are being removed from a new outer shell.
What are the four factors effecting first i.e. ?
i. Nuclear charge (number of protons)
ii. Shielding (number of shells)
iii. Atomic radius
iv. Nuclear attraction
What points on a first i.e. graph do not obey the general trend and why?
2 –> 3 - The fall between groups 2 and 3 marks the start of filling the p subshell. In Be, the outer electron is in a 2s orbital, in B the outer electron is in a 2p orbital.
The 2p orbital in B is of higher energy and experiences more shielding from inner electrons, as it is also shielded by the electrons in the 2s subshell.
Despite the fact that the nuclear charge increases by +1 from Be to B, the difference in shielding and energy means the nuclear attraction is weaker in B, so less energy is required to remove it’s outer electron.
5 –> 6 - The fall between groups 5 and 6 marks the start of electron paring in the p-orbitals in the p-subshell. In N, the outer electron is unpaired in a 2p orbital, in O the outer electron is paired in a 2p orbital.
The paired electrons in oxygen repel slightly, making it easier to remove an electron than in nitrogen.
How do group 2 metals react with oxygen? Let M be the metal
2M (s) + O2 (g) –> 2MO (s)
How do group 2 metals react with water? Let M be the metal
M(s) + 2H2O (L) —> M(OH)2 + H2
Metal + Water —> Metal hydroxide + H2
How do group 2 metals react with acid? Let M be the metal
M(s) + HCl2 (aq) —> MCl2 (aq) + H2O
Metal + Acid —> Salt + Water
What does a reaction need to be balanced?
Same number of atoms on both sides
Same charge on both sides
Same oxidation number total on both sides
What does phenolphthalein indicator do?
Turns pink in alkaline solutions
How does the sum of the first and second IEs tell you about how reactive the metal is with water?
The higher the sum of the first and second I.E, the higher the temperature of the water has to be before reacting
How do group 2 metal oxides react with water? Let M be the metal. What would be seen when this reaction occurs?
MO + H2O —> M(OH)2
Metal oxide dissolves —> White solid forms
What is solubility?
A measure of the ability of a solute to dissolve in a solvent.
What is alkalinity?
A measure of the concentration of hydroxide ions, OH-(aq) present in an alkaline solution.
How do the solubility, alkalinity and pH of the group 2 hydroxides change down the group?
They increase
