s-block Class 11

S Block Class

name of the chapter: S block class

Content Provider: FIITJEE

Lecturer from FIITJEE

Introduction based on NCERT:

The s-block elements of the Periodic Table are those in which the last electron enters the outermost s-orbital. As the s-orbital can accommodate only two electrons, two groups (1 & 2) belong to the s-block of the Periodic Table. Group 1 of the Periodic Table consists of the elements: lithium, sodium, potassium, rubidium, cesium and francium. They are collectively known as alkali metals. These are so-called because they form hydroxides on reaction with water which are strongly alkaline in nature. The elements of Group 2 include beryllium, magnesium, calcium, strontium, barium, and radium. These elements with the exception of beryllium are commonly known as alkaline earth metals. These are so-called because their oxides and hydroxides are alkaline in nature and these metal oxides are found in the earth’s crust*. Among the alkali metals, sodium and potassium are abundant and lithium, rubidium, and caesium have much lower abundances (Table 10.1). Francium is highly radioactive; its longest-lived isotope 223Fr has a half-life of only 21 minutes. Of the alkaline earth metals, calcium and magnesium rank fifth and sixth in abundance respectively in the earth’s crust. Strontium and barium have much lower abundances. Beryllium is rare and radium is the rarest of all comprising only 10–10 percent of igneous rocks† (Table 10.2, page 299). The general electronic configuration of s-block elements is [noble gas]ns1 for alkali metals and [noble gas] ns 2 for alkaline earth metals.

Lithium and beryllium, the first elements of Group 1 and Group 2 respectively exhibit some properties which are different from those of the other members of the respective group. In these anomalous properties, they resemble the second element of the following group. Thus, lithium shows similarities to magnesium and beryllium to aluminum in many of their properties. This type of diagonal similarity is commonly referred to as diagonal relationship in the periodic table. The diagonal relationship is due to the similarity in ionic sizes and /or charge/radius ratio of the elements. Monovalent sodium and potassium ions and divalent magnesium and calcium ions are found in large proportions in biological fluids. These ions perform important biological functions such as maintenance of ion balance and nerve impulse conduction.

Embedded pdf:

Comments

Periodic Table Shortcut

Periodic table shortcut Name of the page: shortcut for periodic table Done by: FIITJEE Student Applicable for all the classes What is a Periodic Table? a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns. The periodic table, also known as the periodic table of elements, is a tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties. The structure of the table shows periodic trends. who invented the periodic table? many collections of scientists invented it. Embedded PDF:

powerpoint metals and non metals

PowerPoint presentation of metals and nonmetals name of the chapter: Metals and nonmetals Content Provider: FIITJEE Lecturer from FIITJEE an intro that just known to us (recall): Metals are described as chemical elements that readily lose valence electrons to form positive ions (cations). Examples : Aluminium, copper, iron, tin, gold. Around 90 of the total 118 elements are metals. To know more about Metals, visit Physical Properties Physical Properties of Nonmetals Occur as solids, liquids, and gases at room temperature Brittle Non-malleable Non-ductile Non-sonorous Bad conductors of heat and electricity Exceptions in Physical Properties Alkali metals (Na, K, Li) can be cut using a knife. Mercury is a liquid metal. Lead and mercury are poor conductors of heat. Mercury expands significantly for the slightest change in temperature. Gallium and cesium have a very low melting point Iodine is non-metal but it has luster. Graphite conducts electricity. Diamond conducts heat

Dark Matter And Dark Energy

Dark matter and dark energy Formation of dark energy – When the universe formed after the big bang theory. It started as a small ball of energy, began expanding, and still continues. – However, the thing that puzzles scientists are that instead of the expansion slowing down its rate is increasing, going against normal physics. Formation of dark energy – This explains the occurrence of energy causing the expansion which scientists term as dark energy. – According to scientists 68% of the universe is dark energy, 27% is dark matter and only 5% is what we currently can observe. – The theory to this was first given by Einstein’s long-forgotten gravity theory which consisted of a cosmological constant. Why is there dark energy? – Scientists have now given 3 explanations for dark energy: – The first is of course Einstein's theory of gravity. – a new theory could include some kind of fi

FIITJEE Chemistry

Search This Blog