Periodic Trends - Chemistry LibreTexts
Does it follow the same trend that ionization energy follows on the This is a loose connection, not a real causation for one or the other. Periodic Trends in Electron Affinity Say Thanks to the Authors Click to reduce the cost of textbook materials for the K market both in the U.S. and worldwide. . the relationships between atomic size, ionization energy, and electron affinity. Major periodic trends include: electronegativity, ionization energy, electron affinity, . The relationship is given by the following equation.
Atomic size gradually decreases from left to right across a period of elements. This is because, within a period or family of elements, all electrons are added to the same shell.
However, at the same time, protons are being added to the nucleus, making it more positively charged.
The effect of increasing proton number is greater than that of the increasing electron number; therefore, there is a greater nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom's shell closer to the nucleus.
The valence electrons are held closer towards the nucleus of the atom. As a result, the atomic radius decreases. The valence electrons occupy higher levels due to the increasing quantum number n.
Note Atomic radius decreases from left to right within a period. This is caused by the increase in the number of protons and electrons across a period. Atomic radius increases from top to bottom within a group. This is caused by electron shielding. Melting Point Trends The melting points is the amount of energy required to break a bond s to change the solid phase of a substance to a liquid. Because temperature is directly proportional to energy, a high bond dissociation energy correlates to a high temperature.
Melting points are varied and do not generally form a distinguishable trend across the periodic table.
Ionization Energy and Electronegativity
However, certain conclusions can be drawn from the graph below. Metals generally possess a high melting point. Most non-metals possess low melting points.
The non-metal carbon possesses the highest boiling point of all the elements. The semi-metal boron also possesses a high melting point. Chart of Melting Points of Various Elements Metallic Character Trends The metallic character of an element can be defined as how readily an atom can lose an electron. From right to left across a period, metallic character increases because the attraction between valence electron and the nucleus is weaker, enabling an easier loss of electrons.
Metallic character increases as you move down a group because the atomic size is increasing. When the atomic size increases, the outer shells are farther away. The principal quantum number increases and average electron density moves farther from nucleus. Note Metallic characteristics decrease from left to right across a period.
Metallic characteristics increase down a group. Generally, nonmetals have more positive E than metals. Atoms whose anions are more stable than neutral atoms have a greater E.
Chlorine most strongly attracts extra electrons; mercury most weakly attracts an extra electron. The electron affinities of the noble gases have not been conclusively measured, so they may or may not have slightly negative values.
E generally increases across a period row in the periodic table prior to reaching group This is caused by the filling of the valence shell of the atom; a group 17 atom releases more energy than a group 1 atom on gaining an electron because it obtains a filled valence shell and therefore is more stable. In group 18, the valence shell is full, meaning that added electrons are unstable, tending to be ejected very quickly.
Counterintuitively, E does not decrease when progressing down the rows of the periodic table, as can be clearly seen in the group 2 data. Therefore, the atoms that require a large amount of energy to release an electron will most likely be the atoms that give off the most energy while accepting an electron. In other words, nonmetals will gain electrons 2 www.
Periodic Trends in Electron Affinity most easily since they have large electron affinities and large ionization energies. Metals will lose electrons since they have the low ionization energies and low electron affinities.
Define electron affinity and write an example equation. Choose the element in each pair that has the lower electron affinity. Why is the electron affinity for calcium higher than that of potassium? Which of the following will have the largest electron affinity?Periodic Trends: Electronegativity and Electron Affinity
Which of the following will have the smallest electron affinity? Place the following elements in order of increasing electron affinity: Tl, Br, S, K, Al.
- Electron affinity
- Difference Between Electronegativity and Electron Affinity
- CHEMISTRY COMMUNITY
Describe the general trend for electron affinities in period 2. Why does sulfur have a greater electron affinity than phosphorus does?