GROUP 7 Flashcards

1
Q

What are group 7 elements called?

A

Halogens

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2
Q

What are halogens?

A

Diatomic non-metals with colored vapours

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3
Q

What is fluorine at room temperature?

A

Pale yellow gas

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4
Q

What is chlorine at room temperature?

A

A green gas

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5
Q

What is bromine at room temperature?

A

Red-brown liquid

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6
Q

What is iodine at room temperature?

A

A black solid

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7
Q

What happens to atomic radii down group 7, and why?

A

Atomic radii increases - This is because each element down the group has one more filled outer energy level than the one above. This means there is a greater distance between outer electrons and positive nuclei.

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8
Q

Define electronegativity

A

A measure of the tendency to attract a pair of electrons in a covalent bond

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9
Q

What does electronegativity depend on?

A
  1. Nuclear charge
  2. Distance between the nucleus and outer energy level electrons
  3. Shielding
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10
Q

What happens to electronegativity down group 7 and why?

A

Decreases - As shielding and atomic radii increases, there is less of an attraction between the positive nuclei and electrons,so it is harder to gain them.

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11
Q

What is unexpected about the F-F bond?

A

It is unexpectedly weak, compared with the rest of the halogens. The small size of the atom leads to repulsion between non-bonding electrons because they are so close together.

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12
Q

What happens to melting and boiling points down group 7?

A

Increase - As larger atoms have more electrons, so more van der waals, so greater energy is required to overcome these bonds

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13
Q

How do halogens react?

A

They react usually by gaining electrons to form negative ions. These reactions are redox reactions.

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14
Q

What happens to oxidizing ability down group 7 and why?

A

Decreases - Oxidizing agents must be able to accept electrons, and further down the group atomic radii and shielding increases so the attraction between positive nuclei and electrons is weaker, so it becomes harder to oxidize as electrons cannot be easily gained.

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15
Q

How do halogens react with metal halides?

A

Via displacement reactions - the more reactive halogen displaces the less reactive halogen

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16
Q

What happens to reactivity down group 7?

A

Decreases - halogens gain electrons to react, and going down the group there is more shielding due to greater amounts of energy levels as well as a greater distance to positive nuclei, so it becomes harder to gain an electron as there isn’t a lot of attraction.