Why is fluorine more reactive than iodine in terms of electrons?
The short answer is that in the halogen group, electronegativity is higher and there is less electron shielding of the nucleus at the top of the group. This means fluorine/chlorine is better at attracting electrons into its outer shell and forming an ion than the larger halogens like bromine/iodine below.
Fluorine is more reactive than any other halogens because of the size of its atom. As the size of atom of flourine is smaller, outer shell is closer to the nucleus and for this reason if a new electron come near to this atom nucleus will attract very fast.
This means Fluorine has a smaller atomic size than Chlorine, which implies that it is more electronegative than Chlorine. The tendency to accept an electron to get a stable valence shell configuration in Fluorine is higher than that of Chlorine, which makes Fluorine more reactive.
Fluorine has the shortest atomic size of all the halogens. As a result, the nuclear attraction on the furthest electrons is greatest. Among the halogens, fluorine is the most reactive.
Among the halogens, fluorine, chlorine, bromine, and iodine, fluorine is the most reactive one.
Due to small size,high electronic density,greater inter electronic repulsion(lower F−F bond energy)F2 is highly reactive among halogens. Hence the order, F2>Cl2>Br2>I2.
Fluorine has higher ionization energy than iodine because the size of fluorine is smaller than the iodine. This suggests that fluorine has a lower shielding effect. As a result, the nucleus of fluorine attracts more valence electrons than that of iodine.
Cl can gain an electron more easily than iodine - Cl more reactive. This is because Cl is higher up Group 7 than iodine (Cl: 2,8,7 electron configuration). Cl outer shell closer to nucleus (and less shielded) than iodine outer shell. Therefore Cl has greater attraction for an electron.
The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.
Since size of chlorine is bigger than fluorine hence the electrons being farther away from the nucleus experience a lesser force of attraction , thus electron negativity of chlorine is less than fluorine.
What makes fluorine the most reactive nonmetal?
Fluorine is the most reactive non-metal because it is the most electronegative of all of the non-metal elements of the periodic table. Due to its strong electro negativity & small size, Fluorine has a strong tendency to accept electrons from other atoms or ions.
The most reactive nonmetal is fluorine. Fluorine is a halogen, which is Group 17 on the periodic table, and the halogens are the most reactive nonmetals.

Fluorine is the most chemically reactive element. It reacts, often very vigorously, with all of the other elements except oxygen, helium, neon and krypton. Fluorine is the most electronegative element. This means that in molecules fluorine attracts electrons more powerfully than any other element can.
Reasons for Fluorine have higher ionization energy than Iodine: Fluorine's size is lower than that of iodine, it has higher ionization energy than iodine. Fluorine, on the other hand, appears to have a smaller shielding effect. As a result, fluorine's nucleus attracts more valence electrons than iodine's.
Solution: Consulting a periodic table reveals that fluorine is a second-row element whereas iodine is a fifth-row element, so F- is a smaller ion than I-. Both of these ions carry a -1 formal charge, but this charge on F- is more concentrated than the charge on I-. Thus F- is a stronger base than I-.
As a result, iodine should be the most reactive halogen, according to this hypothesis. However, this is not the case. Fluorine, on the other hand, is the most reactive halogen.
This is because interhalogen compounds are more reactive than halogens (except fluorine) as X−X′ bond in interhalogens is weaker than X−X bond in halogens except F−F bond due to low bond dissociation energy of interhalogen bonds.
Hence, ICl is most reactive.
The reactivity of the group 2 elements increase as you go down the group. This is because, as explained previously, it is much easier to remove an outer shell electron as you go further down the group (lower ionisation energies).
Since fluorine has a smaller size than chlorine, the electron-electron repulsion is very high, which resists the addition of any further electron to the atom. Thus the electron affinity follows the order – iodine < bromine < fluorine < chlorine.
Does fluorine or iodine have more electrons?
The neutral fluorine atom has a smaller atomic radius than the neutral iodine atom because it is located higher in the halogen group and has much fewer total electrons.
Down the group, the size of the element increase due to the increase of the number of shells in the element. So, the electronegativity of the elements decreases down the group. The electronegativity of iodine is less than that of fluorine because I-atom is greater than F-atom.
This is because down the group size increases and the tendency to pull electrons towards the nucleus decreases. As a result electronegativity decreases and then reactivity also decreases.
Iodine is lower down in group 7 and therefore less reactive than chlorine and bromine. Iodine is not able to displace either of these halogens, so no colour change is seen as no displacement reaction happens.
Reactivity decreases down the group. So correct order is F>Cl>Br>I.
The reactivity of Group 1 elements increases as you go down the group because: the atoms get larger. the outer electron gets further from the nucleus. the attraction between the nucleus and outer electron gets weaker – so the electron is more easily lost.
Reactivity is an element's ability to ionize (gain or lose electrons) or share electrons. More reactive elements tend to gain or lose electrons. Less reactive elements tend to share electrons. So, we can generally think of reactivity in terms of electronegativity and/or electron affinity.
Alkali metals are highly reactive because they readily lose the single electron in their outermost shell.
Due to fluorine's very small atomic radius, the space surrounding its nucleus is also very small, thereby increasing the attraction between the incoming electron and the fluorine nucleus–and, by extension, its electron affinity.
The addition of an extra electron to the valence shell of the fluorine atom produces a strong electron-electron repulsion, as a result, low energy is released which is responsible for the low electron affinity of the fluorine atom.
How does fluorine have the highest electronegativity?
2nd .:- Fluorineis the most electronegative element because it has 5 electrons in it's 2P shell. The optimal electron configuration of the 2P orbital contains 6 electrons, so since Fluorine is so close to ideal electron configuration, the electrons are held very tightly to the nucleus.
In fact, being the most electronegative element, fluorine is the atom with the greatest tendency to attract electrons from other elements towards itself.
As fluorine is the most electronegative of all the non-metals in the periodic table, therefore, it is the most reactive non-metal. Fluorine has a high tendency to receive electrons from other atoms or ions due to its strong electro negativity and tiny size. As a result, all other substances are oxidized.
In the periodic table, cesium is the most reactive metal while fluorine is the most reactive nonmetal.
Reactions of Fluorine
Fluorine bonds with almost any element, both metals and nonmetals, because it is a very strong oxidizing agent. It is very unstable and reactive since it is so close to its ideal electron configuration.
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reactive, as it reacts with all other elements except for the light inert gases.
- Melting point: 53.48 K (−219.67°C, −363.41°F)
- Boiling point: 85.03 K (−188.11°C, −306.60°F)
- Density (at STP): 1.696 g/L.
- Density when liquid (at b.p.): 1.505 g/cm3
- Triple point: 53.48 K, 90 kPa.
- Critical point: 144.41 K, 5.1724 MPa.
- Heat of vaporization: 6.51 kJ/mole.
The most reactive nonmetal is fluorine. Fluorine is a halogen, which is Group 17 on the periodic table, and the halogens are the most reactive nonmetals. This is because they all have one empty space in their valence electron shells.
This is because group 7 elements react by gaining an electron. As you move down the group, the amount of electron shielding increases, meaning that the electron is less attracted to the nucleus. For this reason, fluorine is the most reactive halogen and astatine is the least reactive of the halogens.
Fluorine's electron affinity is actually less than chlorine's. Fluorine is a small atom with very high electron density where the bonding electrons are being attracted into. This decreases its electron affinity to being lower than that of Cl.
Which element is the most reactive and why?
Answer: Cesium is the most reactive element since it is the second from the bottom of this group, has six electron shells, and exhibits the characteristics of a reactive atom.
fluorine (F), most reactive chemical element and the lightest member of the halogen elements, or Group 17 (Group VIIa) of the periodic table. Its chemical activity can be attributed to its extreme ability to attract electrons (it is the most electronegative element) and to the small size of its atoms.
Since Chlorine (Cl) lies below Fluorine in the periodic table, Fluorine is the most reactive non-metal.
Flourine is the most react element in the period table, this is due to it having an almost full outer electron shell of 7 electrons, its outer most shell being closer to the nucleus than other elements in Group 7.
Atoms of all the halogens have seven valence electrons. The halogen atoms are very close to a stable electron configuration. This explains why halogens are reactive. The halogen atoms get their octet by forming ionic or covalent bonds with other atoms.
In the periodic table, cesium is the most reactive metal while fluorine is the most reactive nonmetal.
As fluorine is the most electronegative of all the non-metals in the periodic table, therefore, it is the most reactive non-metal. Fluorine has a high tendency to receive electrons from other atoms or ions due to its strong electro negativity and tiny size. As a result, all other substances are oxidized.
Fluorine is the most chemically reactive element. It reacts, often very vigorously, with all of the other elements except oxygen, helium, neon and krypton. Fluorine is the most electronegative element. This means that in molecules fluorine attracts electrons more powerfully than any other element can.
As you go down group 7, reactivity of the halogens decreases because: The atomic mass of the halogens increases. They increase in electron shells; so the atoms are larger as you go down the group. Therefore, the attraction of the outer electron to the nucleus decreases as you go down group 7.
Metals with a greater total number of electrons tend to be more reactive as their outermost electrons (the ones which will be lost) exist further from the positive nucleus and therefore they are held less strongly.
Which elements are most reactive and least reactive?
- Cesium.
- Francium.
- Rubidium.
- Potassium.
- Sodium.
- Lithium.
- Barium.
- Radium.
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