Periodic Properties | Part 1 | Effective Nuclear Charge and Trends | NEET 2024 | Akansha Karnwal

Unacademy NEET・2 minutes read

The periodic table groups elements based on their electronic configuration and helps determine various properties. Understanding concepts like effective nuclear charge and shield effect are essential in chemistry.

Insights

  • Understanding the periodic table involves recognizing elements' periods, groups, and blocks based on electronic configurations, with the highest n value determining an element's period and block, while the group is determined by valence electrons.
  • Effective nuclear charge is a critical concept in chemistry, influenced by shielding effects and Slater's rule, with left-to-right movement in a period increasing attraction due to the rise in protons, impacting atomic radius and bonding.
  • The importance of discipline and pushing beyond comfort zones is highlighted through the 75 Hard Challenge, emphasizing the necessity for strength, dedication, and growth in academic pursuits, including regular practice, revision, and structured study schedules.

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Recent questions

  • What is the significance of understanding periodic properties in chemistry?

    Understanding periodic properties in chemistry is crucial for mastering inorganic chemistry. It involves starting with comprehending groups and periods on the periodic table, which consists of 18 groups and 7 periods. The groups are determined by the number of valence electrons in a subshell, while identifying an element's period involves finding the highest n value in its electronic configuration. By understanding an element's electronic configuration, one can determine its period, block, and group on the periodic table accurately. This knowledge is essential for analyzing electronic configurations to identify an element's properties and practical applications in chemistry.

  • How is the effective nuclear charge calculated in chemistry?

    The effective nuclear charge in chemistry is determined by the charge within the nucleus of an atom, influenced by the presence of neutrons and protons. It is the actual charge experienced by an electron, affected by the shielding effect caused by intervening electrons in the inner shells. The effective nuclear charge can be calculated by subtracting the shielding constant from the atomic number, aiding in understanding the attraction between the nucleus and electrons. This concept is fundamental in chemistry, as it helps explain the screening effect and its impact on the effective nuclear charge, essential for analyzing atomic properties accurately.

  • What is the role of Wonderwall forces in chemistry?

    Wonderwall forces in chemistry play a significant role in interactions between noble gas atoms and molecules. These forces occur due to attraction between atoms, despite noble gases not forming bonds. The Wonderwall radius, influenced by Kovalenko's effect, is greater than the metallic radius due to the shorter distance between nuclei. Understanding Wonderwall forces is crucial for comprehending atomic interactions and attractions, providing insights into the behavior of noble gases and their unique properties in chemistry.

  • How does the atomic radius change when moving within the periodic table?

    The atomic radius changes when moving within the periodic table based on specific trends. Moving left to right in a period increases the effective nuclear charge, leading to a decrease in atomic radius. Conversely, moving top to bottom in a group adds new shells, increasing the atomic radius due to the addition of new shells. This general trend of atomic radius decreasing when moving left to right and increasing when moving top to bottom in a group is essential to grasp for understanding the size variations of atoms across the periodic table.

  • What is the 75 Hard Challenge mentioned in the text?

    The 75 Hard Challenge mentioned in the text emphasizes the importance of maintaining discipline and pushing oneself beyond comfort zones for personal growth. It is a challenging task that spans two months, requiring strength, discipline, and dedication to achieve desired results. Completing the challenge involves changing oneself and the world, focusing on self-improvement and overcoming obstacles. The challenge highlights the significance of pushing boundaries, maintaining discipline, and striving for success, especially in academic pursuits, to foster growth and development.

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Summary

00:00

Mastering Chemistry: Periodic Table and Electronic Configurations

  • The syllabus for chemistry will be completed in 40 to 50 days, with a focus on organic chemistry concepts.
  • Quantum numbers and electronics were covered in a practice class, with active participation and question-solving.
  • Special classes on these topics are free on Unacademy, with high student engagement and correct answers.
  • Periodic properties are crucial for mastering inorganic chemistry, starting with understanding groups and periods on the periodic table.
  • The periodic table consists of 18 groups and 7 periods, with groups determined by the number of valence electrons in a subshell.
  • Identifying an element's period involves finding the highest n value in its electronic configuration.
  • The last electron's subshell determines the block an element belongs to, with group number based on the number of valence electrons in that subshell.
  • Elements entering the p subshell have different group numbers than those in the s subshell.
  • Understanding an element's electronic configuration helps determine its period, block, and group on the periodic table.
  • The practical application of these concepts involves analyzing electronic configurations to identify an element's properties accurately.

15:24

Determining Period and Group Numbers in Chemistry

  • The value of the biggest shell is three, corresponding to the highest n value.
  • The block number for an element is determined by the highest n value, with the last electron entering the p block.
  • To find the group number for a P block element, add the number of electrons present in the np1 subshell to 12.
  • The group number for an element can be calculated by adding the number of electrons in the d subshell to 12.
  • The period number for an element is determined by the highest n value in the electronic configuration.
  • The group number for a D block element can be found by comparing the number of electrons in the nsx-v and 1dy subshells.
  • F block elements have their last electron in the f subshell, belonging to the F block.
  • The period number for F block elements is determined by the highest n value in the electronic configuration.
  • All F block elements belong to the third group, as shown in the periodic table.
  • Effective nuclear charge is the charge within the nucleus of an atom, determined by the presence of neutrons and protons.

29:59

Understanding Sodium's Atomic Structure

  • Positive charge on the nucleus indicates a neutral or positive state.
  • Sodium's atomic number is 11, with a mass number of 23.
  • The atomic number and mass number help determine the electrons, protons, and neutrons in an atom.
  • For a neutral atom, the number of electrons equals the number of protons.
  • Sodium, with an atomic number of 11, has 11 electrons and 11 protons.
  • The mass number of sodium is 23, with 12 neutrons.
  • The nucleus of sodium carries a positive charge due to its protons.
  • The effective nuclear charge is the actual charge experienced by an electron.
  • Intervening electrons in the inner shells shield the outer electrons from the nucleus, known as the screening effect.
  • The screening effect or shield effect helps understand the concept of effective nuclear charge.

44:20

Understanding Shielding in Chemistry: Key Concepts

  • Screening and shield effect are crucial concepts to understand in chemistry.
  • The electron of interest is the focus when calculating effective nuclear charge.
  • The nucleus and intervening electrons play a significant role in determining shielding effectiveness.
  • The order of shield power is crucial, with S orbital being the most effective.
  • Shielding can be either effective or poor, impacting the effective nuclear charge.
  • Effective shielding reduces the effective nuclear charge, while poor shielding increases it.
  • Slater's rule aids in calculating the effective nuclear charge based on atomic number and shielding.
  • The effective nuclear charge is determined by subtracting the shielding constant from the atomic number.
  • Understanding the concept of effective nuclear charge is essential in chemistry.
  • The shield effect and its impact on the effective nuclear charge are fundamental principles to grasp.

58:28

Chemistry: Understanding Effective Nuclear Charge and Radius

  • Effective nuclear charge is a crucial concept that dominates in chemistry.
  • Understanding the radius and effective nuclear charge is vital for the entire chapter.
  • Moving left to right in a period increases the effective nuclear charge.
  • The number of electrons increases as you move from lithium to fluorine.
  • The addition of electrons does not significantly increase repulsion due to the same shell.
  • Protons and electrons increase as you move left to right, leading to increased attraction.
  • Attractive forces dominate over repulsive forces due to the increase in protons.
  • Effective nuclear charge increases as you move left to right, leading to increased attraction.
  • Coordination chemistry in the D block is essential for understanding complexation.
  • Atomic radius is determined by the distance between the nucleus and the last shell where electrons are present.

01:13:23

"Atomic Bonds and Wonderwall Forces Explained"

  • Electrons move from atom A to atom B, forming a bond.
  • The nucleus of atom A and B are identified.
  • Atomic orbitals of A and B overlap to form a bond.
  • Internuclear distance between atoms A and B is calculated.
  • Metallic radius is determined by halving the internuclear distance.
  • Noble gases do not form bonds but exhibit Wonderwall forces of attraction.
  • Interaction between iodine molecules involves Wonderwall forces.
  • Wonderwall forces occur between noble gas atoms due to attraction.
  • Repulsion between electrons and protons limits atomic distance.
  • Wonderwall radius is greater than metallic radius due to shorter distance between nuclei.

01:27:43

Kovalenko Radius and Bond Length Calculation

  • The Wonderwall radius is the largest due to Kovalenko's influence.
  • A practice session is scheduled for tomorrow at 3 PM.
  • The method to calculate Kovalenko Radius involves overlapping atoms and measuring the distance between their nuclei.
  • In homoatomic molecules, bonds form between atoms of the same size.
  • Heteroatomic molecules involve bonds between atoms of different sizes, requiring consideration of electronegativity differences.
  • Stevenson Show Maker Equation aids in finding the bond length between atoms with electronegativity differences.
  • The equation involves the radii of the atoms and the electronegativity difference.
  • The bond length is calculated using the equation, ensuring the electronegativity difference is positive.
  • Understanding the general trend of atomic radius is crucial.
  • Detailed teaching of concepts, like effective nuclear charge and shield effect, is emphasized for better comprehension.

01:42:46

"75 Hard Challenge: Growth Through Discipline"

  • The challenge mentioned is named the 75 Hard Challenge, emphasizing the difficulty and the need to push oneself out of the comfort zone.
  • Completing the challenge requires strength and discipline, focusing on changing oneself and the world.
  • The challenge involves maintaining discipline and pushing oneself beyond comfort zones, which is challenging but essential for growth.
  • The challenge spans two months, requiring increased effort and dedication to achieve the desired results.
  • The text discusses the importance of maintaining discipline and pushing oneself to achieve success, especially in academic pursuits.
  • The atomic radius is influenced by factors like effective nuclear charge and repulsion, affecting the size of an atom.
  • Moving left to right in a period increases the effective nuclear charge, leading to a decrease in atomic radius.
  • Moving top to bottom in a group adds new shells, increasing the atomic radius due to the addition of new shells.
  • The text highlights the general trend of atomic radius decreasing when moving left to right and increasing when moving top to bottom in a group.
  • The importance of practice and note-taking in academic studies is emphasized, with a focus on regular revision and solving previous year's questions.

01:57:08

Effective Study Resources and Schedule for Success

  • Detailed mind maps are available for various subjects like Physics, Chemistry, and Biology for Class 11th and 12th, along with flashcards. These resources can be obtained from an academy conducting All India Tests or through an Iconic subscription, with a current discount of Rs. 20 using the code "A LIVE."
  • A structured study schedule is recommended, including attending two-hour daily classes for five days, followed by self-study, revision, and regular testing to ensure efficiency and effectiveness in learning. Weekends are designated for breaks and tests, maintaining a consistent routine for optimal progress.
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