The document discusses the organization and trends of the periodic table of elements. It explains that the modern periodic table arranges elements based on their atomic number and electronic configuration into blocks and periods. Elements in the s-block have valence electrons that fill the ns orbitals, while p-block elements fill p-orbitals. d-block and f-block elements have valence electrons that fill d and f orbitals respectively. Trends in properties like ionization energy and electronegativity are also periodic when moving across or down periods and groups on the table.

1. Source: https://www.priyamstudycentre.com/chemistry/periodic-table-elements
Periodic Table Elements
Periodic table elements in chemistry are organized in order of increasing atomic number or the
full number of protons in the atomic nucleus, names as modern law of periodic table. According
to the modern law of the periodic table, the chemical elements are arranged on the basis of
electronic configuration and properties to classify four categories like s, p, d, and f-block
element.
Modern periodic table
The modern law of the periodic table comes due to the breakdown of Mendeleev's (1861)
scientific classification on the basis of atomic weight or masses of the chemical elements. In the
periodic table chart, the elements are represented by two parts, vertical columns (group) and
horizontal rows (period) in chemistry or chemical science. The initial discovery explained by
Dmitri Ivanovich Mendeleev in 1861 and Mosely in 1911 to the Bohr model or scheme
suggested the scientific development of groups and periods of the periodic table elements.
The modern law of the periodic table suggested that the properties of chemical elements and
their compound or molecule is the periodic function of the atomic number.

2. Periodic table of elements list
According to the above definition and explanation, the long form of the periodic table is labeled
into three units like left, right, and middle sections for learning chemistry or physics in science.
The left section in the table has group IA and IIA define the extremely high electropositive
character but very low ionization energy and always show the positive oxidation number. The
right portion contains groups IIIA, IVA, VA, VIA, VIIA with high electron affinity, and non-
reactive noble gases like helium, neon, argon, krypton, xenon, and radon. The organization of the
middle portion of the periodic table made the relationship between the left and right sections and
contains a list of transition metals or d-block and inner transition or f-block elements.
Periodic table blocks
According to the modern periodic law based on the atomic number and valence shell electron
arrangement of elements, the different types of metals and non-metals in chemistry are organized
to form s, p, d, and f-block on the periodic table.
s-block elements
The name f-block element in the periodic table is given due to the arrangement of electrons, the
valence electron enters into ns-orbital and filled progressively according to the configuration
rules. Group-1 (hydrogen, lithium, sodium, potassium, rubidium, cesium, and francium) and
group-2 (beryllium, magnesium, calcium, strontium, barium, and radium) belong to these classes
with valence shell electron configuration, ns1→2
, where n = principle quantum number, or the
number of periods.
p-block Elements
P-block on the periodic table organizes by progressively filled p-orbital in valence shell
electronic structure but helium is an exception with electron arrangement 1s2
. Group-3, 4, 5, 6, 7,
and noble gases belong to p-block elements. Since the second period of p block elements like
boron, carbon, nitrogen, oxygen, fluorine, and argon have filled s-orbitals with valence shell
electron configuration, 2s2
2p1→6
, where n = number of period.
d-block and f-block elements
The name d-block (transition series) or f-block (inner transition series) on the periodic table is
used due to the presence of progressively filled d or f-orbitals in the valence shell electronic
structure. The transition or inner transition family forms the ionic chemical bond with metals (s-
block) and covalent bond with metals non-metals (p-block). Therefore, 3d-block elements like
scandium, titanium, vanadium, chromium, iron, cobalt, nickel, copper, and zinc are placed in the
middle of the table between s and p-block with valence shell electronic configuration, 4s0→2
3d1-
10
. The f-block on the periodic table is divided into two series like 4f or lanthanides and 5f or
actinides contain many missing elements discovered or synthesized by the nuclear reaction of
radioactive isotopes.

3. Periodic table trends
Understanding the periodic variation of ionization energy, electron affinity, electronegativity,
acid, and base properties, oxidation number in redox reaction of chemical elements are very
important characteristics for any discussion or information in chemistry or science. In learning
chemistry, we summarize physical and chemical properties along the group and period.
When we moving down in a group, the size and electropositive character of atoms increases. The
ionization energy usually decreases but in many cases increases due to shielding electron or
effective nuclear charges. The lower member of crystalline solid metals like silver (Ag), gold
(Au), cadmium (Cd), and mercury (Hg), the ionization energy increases. Electronegativity and
electron affinity generally decreases but sometimes apparent some exceptions. The electron
affinity trend of the second-row chemical element in the periodic table is usually lower than the
third row.
Periodic table with electron configuration
The pair of elements are arranging diagonally to each other in the period table to describe simple
relation or chemical properties like electric polarization of contents in chemistry. The diagonal
pair like beryllium and aluminum have a similar change/size ratio since the size increasing to the
lower period while the charge increasing to the right but this rule cannot be work completely for
all the periodic table elements.
Interesting facts in the periodic table explaining the common connection between electronic
structure and periodically accommodation capacities purpose of chemical elements in short form.
For example, 1s orbital can have only two electrons; hence period one contains only two
elements. Period-VI includes 6s, 4f, 5d and 6p orbitals in valence shell electronic structure with
total of (2 + 14 + 10 + 6) = 32 elements from cesium to radon. The simplified scientific formula
in chemistry uses to calculate the number of chemical elements in each period of the periodic
table families.