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Similar to PERIODIC TRENDS PowerPoint presentation.ppt
PERIODIC TRENDS PowerPoint presentation.ppt
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- 2. QUESTION? 1. Why doyou think atoms gets smaller across a period? 2. Why should metals lose electrons more easily than non-metals? 3.What might happen to reactivity if an atom holds it electrons?
- 3. Today’s lesson, youare able to: Define atomic radius, ionization energy, electronegativity, and metallic character; and Create graphs or diagrams that illustrate periodic diagrams (e.g.,atomic radius vs, atomic number)
- 4. Trends in thePeriodic Table The arrangement of elements in the periodic table into groups and periods with predictable properties allows us to assume certain patterns in the electron configurations. Other properties of elements follow predictable patterns in the periodic table: Atomic Radius Ionization Energy Metallic Character Electronegativity
- 5. Atomic radiusis ½ the distance between the nuclei of 2 like atoms ATOMIC RADII
- 6. Group Trend –As you go Group Trend – As you go down a column, atomic radius down a column, atomic radius increases. increases. As you go down, e As you go down, e- - are filled into orbitals that are farther away are filled into orbitals that are farther away from the nucleus (attraction not as strong). from the nucleus (attraction not as strong). Periodic Trend – As you go across a period (L to R), atomic Periodic Trend – As you go across a period (L to R), atomic radius decreases. radius decreases. As you go L to R, e As you go L to R, e- - are put into the same orbital, but more p are put into the same orbital, but more p+ + and e and e- - total (more attraction = smaller size). total (more attraction = smaller size).
- 8. ATOMIC RADIUS As youmove across the period you gain electrons but you also gain protons. More + protons hold their electrons tighter As you move down the group you gain more electrons which are in electron orbitals further from the nucleus. The nucleus has less pull the further out you move.
- 9. IONIZATION ENERGY (IE) Ionization Energy is the energy required to remove 1 electron from an atom. (Make a + ion) Low IE – Easy to remove the electron High IE – Hard to remove the electron As you move DOWN a group ionization energy DECREASES As you move LEFT to RIGHT across a period ionization energy INCREASES
- 10. IONIZATION ENERGY Atoms onthe left of the periodic table give up electrons easily to achieve a more stable electron configuration. The valence electrons in atoms lower in the group experience less pull from the + protons in the nucleus and are easier to remove. Lower IE Low IE High IE The Noble Gases have the highest IE of all because they are in the most stable configuration.
- 11. ELECTRONEGATIVITY Electronegativity isthe tendency of an atom to attract electrons in a compound. The higher the electronegativity, the more the atom is able to attract electrons to itself. As you move DOWN a group Electronegativity DECREASES As you move LEFT TO RIGHT across a period Electronegativity INCREASES
- 12. ELECTRONEGATIVITY As you godown a group, electronegativity decreases because the bonding pair of electrons is increasingly distant from the attraction of the nucleus. Electronegativity increases across a period because the number of charges on the nucleus increases. That attracts the bonding pair of electrons more strongly.
- 13. METALLIC CHARACTER Metalliccharacter is the tendency of an element to be shiny, silver, malleable, ductile and to react to form positive ions As you move DOWN a group metallic character INCREASES As you move LEFT TO RIGHT across a period metallic character DECREASES
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- 18. GENERALIZE SOME POINTS 1. Why is it important to study periodic trends in understanding how elements behave in chemical reactions used in industries and daily life? 2.How does analysing periodic trends help scientist design safer materials, such as non-reactive containers or corrosion-resistant metals?