a type of periodic table in which He is moved from the top of group 18 (noble gases) to the top of group 2 (alkaline earth metals). It also places the s-block elements on the right, so that the blocks are arranged in f, d, p, s format.
1. Advantages: Has symmetrical lengths corresponding to electron configuration (2,2,8,8,18,18).
2. Disadvantages: Destroys triads and places He with alkaline earths, which it is not similar to. Based on n+l rule.
principle quantum number
n= 1, 2, 3...
1. Determines the shell the electron is in. The shell is the main component that determines the energy of the electron (higher n corresponds to higher energy), as well as nuclear distance (higher n means further from the nucleus).
2. The row that an element is placed on the periodic table tells how many shells there will be. Helium (n = 1), neon (n = 2), argon (n = 3), etc.
Each shell with quantum number n has n subhells, n^2 orbitals and can hold up to 2n^2 electrons.
i.e. n = 3 has 3 subshells (s, p, d). It contains 9 orbitals: 3s, 3px, 3py, 3pz, 3dxy, 3dxz, 3dyz, 3dz2, 3dx2-y2
magnetic quantum number, describes quantization of direction (or orientation) of angular momentum (tells you what direction the electron is facing.
Given a certain l, ml is an interval ranging from -l to +l, so it can be zero, a negative integer, or a positive integer.
1. Determines the orbital in which the electron lies.
2. Example: If n=3, and l=2, then what are the possible values of ml ? Answer: Since ml must range from -l to +l, then ml can be: -2, -1, 0, 1, or 2.
4th; electron spin quantum number
1. Unlike n, l, and ml, the electron spin quantum number ms does not depend on another quantum number. It designates the direction of the electron spin and may have a spin of +1/2, represented by ↑, or -1/2, represented by ↓. This means that when ms is positive the electron has an upward spin, which can be referred to as "spin up." When it is negative, the electron has a downward spin, so it is "spin down." (+1/2 h/2pi, and -1/2 h/2pi)
2. The significance of the electron spin quantum number is its determination of an atom's ability to generate a magnetic field or not. Besides the magnetism related to its motion and anticipated by the other quantum numbers, there is an intrinsic magnetism that is quantized.