Classification of elements and periodic properties class 11 | Chapter 3 Chemistry | CBSE JEE NEET

LearnoHub - Class 11, 12・2 minutes read

The video covers Class XI Chemistry Classification of Elements and Predictability in Properties, highlighting the history of element classification and the modern periodic table. It discusses electronic configurations, block elements, metallic and non-metallic characters, trends in atomic radius, and factors affecting electron removal and electronegativity.

Insights

  • Newland's work initiated the classification of elements by atomic mass, while Ma's contributions further refined the periodic table based on chemical properties, culminating in the modern table organized by atomic number.
  • The electronic configuration of elements dictates their properties, with trends such as metallic character, atomic radius, and electronegativity varying across periods and groups, showcasing how the arrangement of electrons influences the behavior of elements in different categories like alkali metals, noble gases, and transition metals.

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Recent questions

  • What is the basis of the modern periodic table?

    Arranging elements by atomic number.

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Summary

00:00

"Chemistry: Classification of Elements and Properties"

  • The video covers the entire Class XI Chemistry Classification of Elements and Predictability in Properties.
  • After watching the video, all lessons will be available on a clear platform for easy access.
  • Classification of elements is crucial and should be organized for easy reference.
  • The history of classification of elements began with Newland's work on arranging elements by increasing atomic mass.
  • Ma's work further developed the periodic table based on chemical properties of elements.
  • The modern periodic table is based on arranging elements by atomic number.
  • Elements within the periodic table exhibit similar properties at regular intervals.
  • The long form of the periodic table organizes elements into periods and groups.
  • The number of elements within each period varies, with some having few and others having many.
  • The naming of newly discovered elements is regulated by IUPAC to avoid confusion, with temporary names assigned until final proof is obtained.

28:11

"Electronic Configuration and Properties of Block Elements"

  • The text discusses the electronic configuration of elements, focusing on block elements and their groupings.
  • Block elements are classified as main group elements or representative elements when they are together in P.
  • The electronic configuration pattern is highlighted, with examples like nitrogen and oxygen showing a consistent pattern.
  • Transition elements, also known as D block elements, act as a bridge between S block and P block elements.
  • The electronic configuration of block elements is detailed, with examples like Uranium showcasing matching patterns.
  • The metallic and non-metallic character of elements is explained, with metals tending to lose electrons and non-metals gaining them.
  • The tendency to lose electrons increases as you move from top to bottom in a group, enhancing the metallic character.
  • Moving from left to right in a period increases the non-metallic character due to the increasing positive charge of the nucleus.
  • The text delves into the properties of metals and non-metals, highlighting their physical characteristics and trends in atomic radius.
  • The atomic radius decreases as you move from left to right in a period due to the increasing positive charge of the nucleus, leading to a smaller size of the atom.

55:16

"Atomic Size and Electron Attraction Trends"

  • Positive-positive electronic use discussed
  • Proton not used, one electron reduced from outer electron, strengthening nuclear charge
  • Electrons pulled towards nucleus, size decreases; electrons repel, size increases
  • Equal number of electrons in elements, but different nuclear charges affect size
  • Energy required to remove electrons varies based on nuclear charge
  • Elements with higher nuclear charge have smaller size due to stronger nucleus
  • Easy electron removal indicates weaker nuclear control
  • Electron configuration affects ease of electron removal
  • Electronegativity determines attraction of electrons towards an element
  • Trends in physical properties like atomic radius and electronegativity vary across periods and groups

01:26:34

Element oxidation states and group behaviors explained.

  • The oxidation state of an element is a fixed charge that combines with other molecules to form a porous molecule by adding both positive and negative charges.
  • To determine the oxidation state, consider the number of electronic items and the balance between positive and negative charges.
  • Elements in certain groups exhibit unique behaviors, with the first element often behaving differently from the rest in the group due to size and bonding availability.
  • The properties of elements are influenced by their electronic configurations, with distinct behaviors observed in different groups such as alkali metals, noble gases, and transition metals.
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