The Periodic Table Flashcards
(18 cards)
What does the periodic table show?
All known elements in order of increasing atomic number.
What do Groups 1 to 0 indicate in the periodic table?
The number of electrons in their outer energy level (shell) of each element in the group.
What do Periods 1 to 7 indicate in the periodic table?
The number of main energy levels of each element in that period.
What do the s, p, and d blocks indicate in the periodic table?
The sub-level being filled with electrons as you go across the table.
What is the first ionisation energy?
The energy required to remove an electron from each atom in 1 mole of gaseous atoms.
Write the equation for first ionisation energy.
M(g) → M+(g) + e-
What is the trend of first ionisation energy down a group?
It decreases.
Why does first ionisation energy decrease down a group?
The outer electron is further from the nucleus and there are more inner shells to shield the outer electron.
What is the general trend of first ionisation energy across a period?
It increases.
What causes the increase in first ionisation energy across a period?
The nuclear charge increases, while the shielding stays the same.
What are the exceptions to the trend in first ionisation energy in groups 3 and 6?
In group 3, the electron is removed from a higher energy sub-shell; in group 6, electrons pair up and repel in an orbital.
What is the first electron affinity?
The energy change when an electron is added to each atom in 1 mole of gaseous atoms.
Write the equation for first electron affinity.
X(g) + e- → X-(g)
What is the trend of first electron affinity down a group?
It decreases.
Why does first electron affinity decrease down a group?
The shell to which the electron is being added is further from the nucleus and has more shielding from inner shells.
What are the exceptions to the trend in electron affinity?
Fluorine (F) and Oxygen (O).
Fill in the blank: Some salts containing the hydride ion, H-, are used in _______.
drying agents.
Write an equation for the first electron affinity of hydrogen to form the hydride ion.
H(g) + e- → H-(g)
