GENERAL KNOWLEDGE

Detailed explanation-1: -Elements are placed in order on the periodic table based on their atomic number, how many protons they have. In a neutral atom, the number of electrons will equal the number of protons, so we can easily determine electron number from atomic number.

Detailed explanation-2: -The periodic table is arranged by atomic weight and valence electrons. These variables allowed Mendeleev to place each element in a certain row (called a period) and column (called a group).

Detailed explanation-3: -In 1869, Russian chemist Dmitri Mendeleev created the framework that became the modern periodic table, leaving gaps for elements that were yet to be discovered. While arranging the elements according to their atomic weight, if he found that they did not fit into the group he would rearrange them.

Detailed explanation-4: -The position of an element, and its chemical properties, on the table is defined by the electronic configuration of its orbitals. Moving horizontally across the table, as the atomic number increases each orbital within an elements highest level electron shell (valence shell) fills up.

Detailed explanation-5: -Elements of the periodic table are arranged in order of increasing atomic number. The periodic law states: “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties."