Electro negativity and its periodic trend.pptx

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1. Electronegativity Outlines: Definition Significance Factors that influence electronegativity Trend in periodic table

2. Definition: Electronegativity is the ability of an atom in a covalent bond to attract shared electrons towards itself . It is a measure of an atom’s ability to pull electrons towards its nucleus and is typically measured on the Pauling scale which ranges from 0 to 4.

3. Significance : It plays role in understanding the properties of their elements and their behavior in chemical reactions. Polarity of covalent bond: Electronegativity differences between atoms in a bond determines the bond polarity.

4. 2- Type of chemical reaction: Electronegativity influences the type of reaction between elements such as ionic or covalent. 3-Physical and chemical properties: Electronegativity affects the boiling point, melting point and solubility of molecules.

5. Factors that influence electronegativity: 1- Atomic number: Electronegativity increases with atomic number, as the number of protons in the nucleus increases. 2-Nuclear charge: Electronegativity increases with nuclear charge, as the positive charge of the nucleus attracts electrons more strongly.

6. 3-Electronic configuration: Elements with full outer shells have low electronegativity as their electrons are less attracted to the nucleus.

7. Trend: Across period: Electronegativity increases left ⬅️ to right as atomic number increases. In group: Electronegativity decreases from top 🔝 to bottom as atomic radius increases.

8. Examples: Flourine have high electronegativity which makes it highly reactive. Hydrogen have medium electronegativity 2.2 results in polar covalent bond with other atoms.⚛️

9. Pauling scale: If electronegativity is less than 1.7 then bond is covalent. Between 1.7 and 2.6 the bond is polar covalent bond. Greater than 2.6 bond is ionic. e.g., hydrogen – 2.2- covalent with oxygen or nitrogen.