10 Questions
What is the effect of increasing nuclear charge on the atomic radius?
It decreases the atomic radius
Which of the following statements is true about ionization energy?
It increases as you go from left to right across a period
What is the trend of electron affinity across a period?
It increases from left to right
What is the relationship between atomic radius and metallic character?
They are directly proportional
What is the significance of the noble gases in the formulation of chemical bonding theories?
They are the most stable, with the exception of helium
What is the correct definition of ionization energy?
The energy required to remove an electron from a gaseous atom
Which of the following statements is true about electron affinity?
It decreases down a group
What is the trend of metallic character across a period?
It decreases from left to right
What is the correct definition of electron affinity?
The energy required to add an electron to a gaseous atom
What is the significance of G.N. Lewis in the context of chemical bonding?
He formulated the first theories on chemical bonding
Study Notes
Electronic Configuration and Quantum Numbers
- Quantum numbers describe the movement of each electron within an atom, specifying energy, size, shape, and orientation of the electron orbital.
- There are four principal quantum numbers: n (Principal Quantum Number), l (Azimuthal/Angular Quantum Number), m (Magnetic Quantum Number), and ms (Spin Quantum Number).
- Quantum numbers are used to determine ionization energy and atomic radius.
The Periodic Table
- J.W.Döbereiner observed that elements could be classified into groups of three (triads), with the middle element's value being the arithmetic mean of the other two elements.
- Newlands suggested that the 62 known elements could be arranged into groups of seven according to increasing atomic mass, proposing the law of octaves.
- Mendeleev proposed that the properties of chemical elements repeat at regular intervals when arranged in order of increasing atomic mass, and predicted the existence and properties of three elements before their discovery.
The Periodic Law
- The periodic law states that the properties of elements recur in a repeating pattern when arranged according to increasing atomic number.
- The law was further explained by the introduction of electron energy levels by Niels Bohr.
Classification of Elements by Groups and Periods
- A vertical column on the periodic table is a group or family of elements, resulting in increasing nuclear charge and decreasing atomic radius across the period.
Ionization Energy
- Ionization energy is the amount of energy required to remove an electron in the gaseous state.
- Ionization energy increases as you go from the bottom to the top in a group, and from left to right across a period of elements.
Electron Affinity
- Electron affinity is the energy change associated with the addition of an electron to a gaseous atom.
- Electron affinity increases generally across the period, from left to right, but decreases down a group.
Atomic Radius and Metallic Character
- Atomic radius decreases across the period, due to increasing nuclear charge.
- Metallic character decreases left to right across a period and from bottom to top in a group, similar to the trend for atomic radius.
Chemical Bonding
- G.N.Lewis formulated the first theories on chemical bonding in 1916.
- Noble gases were observed to be the most stable, with the exception of helium, they all had eight electrons in their outer shell.
Test your knowledge of quantum numbers, electron orbitals, and their applications in atomic physics
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