An important idea, how atoms interact with electrons is called electron gain enthalpy. It clarifies why certain elements more readily produce negative ions, or anions, than others. Here we shall discuss in a concise and clear explanation of electron gain enthalpy, covering its importance, periodic table trends, and practical applications in chemistry.
What is Electron Gain Enthalpy?
Energy transfer that happens when an electron is added to a neutral atom in the gas phase to create a negatively charged ion is known as the electron gain enthalpy. Depending on the atom, this process might either release or need energy. Electron gain enthalpy is regarded as positive when energy is absorbed and negative when it is released.
General reaction can be written as: A(g) + e− → A−(g)
Above case, the electron is added, denoted by e−, and A(g) is a neutral atom in the gaseous form. Resultant type, A−(g) is the negatively charged ion generated after the electron is gained.
Why Does Electron Gain Enthalpy Matter?
How quickly an atom can accept an electron to create a stable anion is explained by idea of electron gain enthalpy. It is how reactive an element is, especially one that isn’t a metal. In ionic bonding situation, elements with higher negative electron gain enthalpy values are more reactive because of their greater tendency to receive electrons and produce stable negative ions.
For example, the extremely negative electron gain enthalpy values of halogens, such as chlorine and fluorine, indicate their strong desire to acquire electrons and form negative ions, which accounts for their high reactivity.
Positive and Negative Electron Gain Enthalpy:-
1. Negative Electron Gain Enthalpy: Electron gain enthalpy is negative if an atom obtains an electron and releases energy in the process. Because non-metals have a strong similarity for electrons, this normally occurs. For example, halogens may easily acquire electrons to form a stable octet configuration, they have negative electron gain enthalpy.
2. Positive Electron Gain Enthalpy: Electron gain enthalpy is positive if an atom needs energy to gain an electron. Noble gases and some metals, whose electron shells are already filled or almost filled and are not restless to pick up new electrons, are more likely to display this. Noble gases, such as argon and neon, have positive electron gain enthalpy due to the fact that their electrical configurations are stable.
Factors Affecting Electron Gain Enthalpy
1. Atomic Size: Electron gain enthalpy of an atom is largely dependent on its size. Nucleus’s attractive force decreases with atom size because of the increased distance between the nucleus and the extra electron. Larger atoms often have lower negative electron gain enthalpy.
2. Nuclear Charge: Electron gain enthalpy is also influenced by effective nuclear charge, or attraction between the nucleus and extra electron. More nuclear charge results in a stronger pull on the extra electron, which raises the enthalpy of the negative electron gain.
3. Electron Configuration: Noble gases and other atoms with stable electronic configurations have positive electron gain enthalpy because they are not in favor of receiving additional electrons. Whereas, elements like halogens that are just one electron from reaching a stable structure have a very negative electron gain enthalpy.
4. Electron-Electron Repulsion: It is possible for an electron to be repelled by other electrons in an atom when it is added. Repulsion is strong in small atoms with densely packed electrons, which in certain situations might cause the electron gain enthalpy to be less negative or even positive.
Trends in the Periodic Table
1. Across a Period: Electron gain enthalpy generally decreases as one moves across a period in the periodic table from left to right. This is because an increase in nuclear charge and a decrease in atomic size make easy the attraction and acceptance of electrons by the atom. On exception of noble gases, halogens are found on the far right of the periodic table, have the highest negative electron gain enthalpy.
2. Down a Group: Electron gain enthalpy decreases with group placement in the periodic table. This is because the extra electron is located farther from the nucleus and the atomic size rises, decreasing the nucleus’s attractive force. Compared to iodine, fluorine has a greater negative electron gain enthalpy.
Applications of Electron Gain Enthalpy
Ionic Bond Formation: In ionic compounds, elements with extremely negative electron gain enthalpy normally produce anions. Cl-,, is created when chlorine (Cl) obtains an electron and is essential for the synthesis of substances like sodium chloride (NaCl).
Predicting Reactivity: Particularly for halogens, electron gain enthalpy is useful in predicting the reactivity of non-metals. Higher reactivity is indicated by more negative values.
Catalysis and Industrial Processes: Catalysis and industrial processes concerning the manipulation of elements to gain electrons, such as chlorination, are influenced by the concept of electron gain enthalpy.
Note
How atoms interact with electrons is electron gain enthalpy. It add to the understand of anion production, element reactivity, and periodic table trends. Electron gain enthalpy is an essential tool in commercial chemistry because it allows chemists to forecast how elements will behave in processes.
Quantity of energy released or absorbed when an electron is added to a neutral atom in the gas phase to create a negative ion is known as the electron gain enthalpy. Energy release is shown by a negative electron gain enthalpy, whereas energy absorption is indicated by a positive value.
Ability of an element to pick up electrons and produce negative ions (anions) is predicted in part by its electron gain enthalpy. It is essential for outline of non-metal reactivity.
Electron gain enthalpy normally becomes more negative because atomic size decreases and nuclear charge increases. Atoms are able to attract and receive electrons more easily as a result.
Electronic configuration, nuclear charge, atomic size, and electron-electron repulsion are some of the variables that affect electron gain enthalpy. Higher nuclear charge smaller atoms normally have higher negative electron gain enthalpy.
Halogens are just one electron away from reaching a stable octet structure, they display extremely negative electron gain enthalpy. Because of this, they are extremely reactive and ready to pick up electrons, which release energy.
Because of their stable electronic structure, noble gases have positive electron gain enthalpy. Since the atom does not prefer to obtain an additional electron, adding an electron requires energy.
Because of the increase in atomic size, electron gain enthalpy decreases as one moves down a group on the periodic table. The extra electron is located farther from the nucleus, the attractive attraction is narrowed and the atom finds it more difficult to acquire electrons.