Group 7 Flashcards
(21 cards)
What is the trend in electronegativity in Group 7 elements and why? (5)
Electronegativity decreases down the group
1. The size of the atom increases.
2. The number of principal energy levels increases
3. There is weaker attraction between the nucleus and electrons in a covalent bond
What is the trend in boiling points in Group 7 elements and why? (3)
Increase down the group
- The size of the atom increases
- There are more Van der Waals forces between the molecules that need to be broken
What is the appearance of fluorine (F₂) at room temperature? (1)
Pale yellow gas
What is the appearance of chlorine (Cl₂) at room temperature? (1)
Pale green gas
What is the appearance of bromine (Br₂) at room temperature? (1)
Dark red/orange liquid
What is the appearance of iodine (I₂) at room temperature? (1)
Dark purple/black solid
What is an oxidising agent and describe trend (2)
Electron acceptor
The oxidising power decreases down the group from fluorine (strongest) to iodine (weakest)
Why does the oxidising power of halogen atoms decrease down the group? (3)
- The size of the atom increases.
- The effect of the nuclear charge is reduced due to shielding.
- The halogen gains electrons less readily.
What is the observation when chlorine (Cl2) is added to a solution of potassium chloride (KCl)? (1)
No visible change
What is the observation when bromine (Br2) or iodine (I2) is added to a solution of potassium chloride (KCl)? (1)
No visible change
Write the ionic equation when chlorine (Cl2) reacts with potassium bromide (KBr). (2)
Cl2 + 2Br- → Br2 + 2Cl-
What is the observation when chlorine (Cl2) reacts with potassium bromide (KBr)? (1)
A yellow solution of bromine (Br2) is formed
What is the observation when bromine (Br2) or iodine (I2) is added to potassium bromide (KBr)? (1)
No visible change
Write the ionic equation when chlorine (Cl2) reacts with potassium iodide (KI). (2)
Cl2 + 2I- → I2 + 2Cl-
Write the ionic equation when bromine (Br2) reacts with potassium iodide (KI). (2)
Br2 + 2I- → I2 + 2Br-
What is the observation when chlorine (Cl2) reacts with potassium iodide (KI)? (1)
A brown solution of iodine (I2) is formed
What is the observation when bromine (Br2) reacts with potassium iodide (KI)? (1)
A brown solution of iodine (I2) is formed
What is the observation when iodine (I2) is added to potassium iodide (KI)? (1)
No visible change
What is a reducing agent and describe trend (1)
Electron donor
The reducing power increases from fluoride (weakest) to iodide (strongest)
Why does the reducing power of halide ions increase down the group? (3)
- The size of the ion increases.
- There is increased shielding.
- It is easier to lose an electron
