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Periodic Table
The Periodic Table is a tabular arrangement of the elements in increasing order oftheir atomic numbers, so that elements with similar properties are in the same column. There are 18 columns, called groups, and seven rows, which are called periods, in the modern periodic table. Questions about the Periodic Table: its history and creation, trends, groups/families, and periods are asked in our Periodic Table category.
11,356 Questions
Why is it when an atomic number increases in a group the size of the atoms increase?
As the atomic number increases within a group, additional electron shells are added to the atom, leading to a greater distance between the outermost electrons and the nucleus. This increase in distance results in a larger atomic radius. Additionally, while the effective nuclear charge increases, the shielding effect from inner-shell electrons mitigates this attraction, allowing outer electrons to be held less tightly and thus increasing atomic size.
Why Francium is not in Mendeleev Periodic Table?
Francium was discovered in 1939, several decades after Mendeleev created his periodic table in 1869. At the time Mendeleev developed his table, francium had not yet been identified, and elements were organized based on their known properties and atomic weights. Additionally, francium is a highly radioactive and unstable element, which made it difficult to study and include in early classifications of elements.
What is the modification of John Dalton's atomic theory?
- All elements are made up of atoms
- Atomos are indivisible and indistructable
- Atoms of a given element are identical in mass and in all other properties
- A compound is formed when the atoms of two or more elements combine
In which group do the elements ussually orm oxides which have the general formula M2O3?
Group 3(III)
Oxides of
Group (I) are M2O
Group (II) are MO
Group(III) are M2O3
Group(IV) are MO2
Group(V) are M2O5 ( Can vary ; NO , N2O , NO2)
Group(VI) are MO3 ( Can Vary ; MO2 MO3)
Group(VII) are M2O7 ( Can Vary)
Group(VIII) are ther Noble (Inert) gases and do not react.
Transition metal/elements can exhibit variable oxidations from MO , M2O3, etcs.,
NB Group (V) , (VI), & (VII) have variable oxidation numbers and so can exhibit various oxides.
NNB 'M' is used to indicate an element , not just a metal .
BaO is the chemical formula for barium oxide, a white solid compound used in the production of ceramics, glass, and other materials. It is known for its high reactivity with water and acids, making it a useful material in various industrial processes.
