What is the trend in the halogens?
What is the trend in the halogens?
The halogens become darker as you go down the group. Fluorine is very pale yellow, chlorine is yellow-green, and bromine is red-brown. Iodine crystals are shiny purple – but easily turn into a dark purple vapour when they are warmed up.
What is the trend in electron affinity down group 7?
As the atom gets bigger, the incoming electron is further from the nucleus and so feels less attraction. The electron affinity therefore falls as you go down the Group.
What is the trend for electron affinity What is electron affinity?
What is the trend for electron affinity? Electron affinity increases upward across periods of a periodic table for the groups and from left to right, because the electrons added to the energy levels get closer to the nucleus, making the nucleus and its electrons more attractive.
Why does electron affinity decrease down group 17?
When moving down a group, the electron affinity generally decreases. This is because as you go down the period table, new valence shells are added increasing the atomic radius. The new orbital is further away from the nucleus, meaning the attraction between the positively charged nucleus and the new electron decrease.
What is the trend in reactivity of halogens?
The non-metal elements in Group 7 – known as the halogens – get less reactive as you go down the group. This is the opposite trend to that seen in the alkali metals in Group 1 of the periodic table .
Why do group 7 elements gain an electron?
The group 7 elements want to gain one more electron so that they have a stable electronic structure. The smaller the atom, the easier it is to grab an electron from another atom, making the atom more reactive. As you go down group 7, the atomic radius increases and it becomes more difficult to attract another electron.
What are group 7 halogens?
The Group 7 elements are called the halogens. They are placed in the vertical column, second from the right, in the periodic table . Chlorine, bromine and iodine are the three common Group 7 elements. Group 7 elements form salts when they react with metals.
What are the trends of group 7 elements?
What are the trends in Group 7 – Halogens? In Group 7, otherwise known as the Halogens, the melting point, boiling point and atomic radius increase as you move down the group. In addition, the reactivity decreases as you move down the group.
Why do halogens have high electron affinity?
The high electron affinities of the halogens are a result of their having an almost complete outer shell of electrons. Because of this overall attraction, energy will be released when the electron is captured by the fluorine atom. Similar reasoning also explains why oxygen also has a high electron affinity.
Do halogens have a negative electron affinity?
Electron affinities are negative numbers because energy is released. The elements of the halogen group (Group 17) gain electrons most readily, as can be seen from their large negative electron affinities. This means that more energy is released in the formation of a halide ion than for the anions of any other elements.
Why does electron affinity decrease down halogens?
Electron affinity decreases down the groups and from right to left across the periods on the periodic table because the electrons are placed in a higher energy level far from the nucleus, thus a decrease from its pull. The increased nuclear charge as you go down the group is offset by extra screening electrons.
Why do the halogens decrease in reactivity?
The reactivity of Group 7 elements decreases down the group. The electrons in the outer shell move further away from the nucleus as we go down the group and the attraction force between the electrons and the nucleus become weaker and weaker. This weaker attraction in the larger atoms makes it harder to gain electron.
