alkali metals periodic table definition chemistry

#Alkali metals periodic table definition chemistry full#

It replaces two older incompatible naming schemes, used by the Chemical Abstract Service (CAS, more popular in the United States), and by IUPAC before 1988 (more popular in Europe). The modern numbering system of 'group 1' to 'group 18' has been recommended by the International Union of Pure and Applied Chemistry (IUPAC) since 1988. There are three systems of group numbering for the groups the same number may be assigned to different groups depending on the system being used. The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms (i.e., the same core charge), because most chemical properties are dominated by the orbital location of the outermost electron. There are 18 numbered groups in the periodic table the 14 f-block columns, between groups 2 and 3, are not numbered. In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. In the periodic table of the elements, each column is a group. Ques 1.Column of elements in the periodic table of the chemical elements

Some monovalent alkali metals are Li+, Na+, K+ etc and divalent alkaline earth metals are Be 2+, Mg 2+, Ca 2+ etc.

The electrode potential of an electropositive element has higher positivity than the standard hydrogen electrode which has a value of zero.The electropositive element or group releases its electrons i.e.Both metals and nonmetals are classified as electropositive and electronegative.The elements in the periodic table are divided into two parts: alkali metal and alkaline earth metals.The electropositivity and the metallic character of the electron also increases from top to bottom in a group.

#Alkali metals periodic table definition chemistry full#

If the outermost shell of an element is less half full then it requires less energy to accept an electron than to lose whereas if it is more than the half electron it is easier to lose. Going from left to right in the periodic table the electropositivity decreases.Going top to bottom down the group, the electronegativity decreases because the atomic number of an element increases down the group and thus the distance between the outermost electrons and the nucleus increases and the atomic radius.Since, electronegativity is opposite of electropositivity, we can say that the periodic trends of an electropositive element is always opposite to the periodic trends of an electronegative element.īelow we have given the periodicity of the element The periodic trends of the electropositive elements can vary depending upon various factors such as the ionisation energy of an element, the metallic character of the element, distance between the outermost electron and the nucleus of an element and the effective nuclear charge on the valence electrons. Periodic Trends in the Electropositive Element Most electronegative element are Fluorine or Chlorine Most electropositive elements are Francium or Cesium Shown by mostly metals such as alkali and alkaline earth metals It forms negatively charged anions by accepting one or more electrons It forms positively charged cations by removing one or more electrons

It has the ability to attract electrons towards itself It is ability of an element to gain or accepts electrons

It refers to the ability of an element to lose electrons in a chemical reaction Magnesium Chloride is useful to treat and prevent the low amount of magnesium in the blood. Therefore from the above mentioned example we can say, the electropositive element Magnesium and the electronegative element Chlorine combined to form an ionic salt named Magnesium Chloride or MgCl2. For example, Magnesium (Atomic Number :12) which has two electron in its outermost orbit lose its electron to form a positively charged cations in order to achieve the nearest noble gas electronic configuration whereas Chlorine (Atomic Number :17) a highly negative elements accepts the two electron to form a positively charged anion in order to complete its stable octet. The electropositive elements lose electrons to electronegative elements to form an ionic compound. The higher the electronegativity character of an element, the lower the electropositive elements and vice versa. Alkali metals or alkaline metals.Įlectropositivity is opposite to the term of electronegativity in which an element accepts an electron from another element to form a negatively charged anion. The ability of an atom to form a cation is mostly shown by the metallic elements of the periodic table i.e. The term Electropositive is generally defined as the tendency of an atom to release its electron to another atom to form a positively charged cation. Periodic trends in the Electropositive element.Difference between the Electropositive and Electronegative.