Periodic Trends - AP Chemistry
- Which element has the lowest electronegativity?
- Francium. Largest atomic size with lowest nuclear charge effect.
- What is the shielding effect?
- Reduction in effective nuclear charge by inner electrons. Core electrons block valence electrons from nuclear attraction.
- What is the trend for oxidation states in transition metals?
- Varies widely, often multiple oxidation states. D-electrons can be lost in different combinations.
- What is the trend for electronegativity across a period?
- Electronegativity increases across a period. Higher nuclear charge increases attraction for electrons.
- What is the trend for metallic character in transition metals?
- Varies slightly but generally high. D-electrons provide consistent metallic bonding across period.
- What is the trend for boiling points across a period?
- Boiling points vary; metals generally increase. Stronger metallic bonding with more valence electrons.
- What is the trend for electron affinity down a group?
- Electron affinity becomes less negative down a group. Increased size and shielding reduce attraction for electrons.
- What is the trend for melting points in alkali metals?
- Melting points decrease down the group. Weaker metallic bonding with larger atomic size.
- What is the trend for atomic radius across a period?
- Atomic radius decreases across a period. Increasing nuclear charge pulls electrons closer with same shielding.
- Which group has the highest ionization energies?
- Noble gases. Stable electron configurations resist electron removal.
- Which group has elements with zero electronegativity?
- Noble gases. Electronegativity undefined for unreactive noble gases.
- How does metallic character change down a group?
- Metallic character increases down a group. Larger size makes valence electrons easier to remove.
- Why do noble gases have low reactivity?
- Noble gases have a full valence shell. Complete octets provide maximum stability and low reactivity.
- What is the trend for electron affinity across a period?
- Electron affinity becomes more negative across a period. Atoms more readily accept electrons due to higher nuclear charge.
- What is the general trend of density across a period?
- Density generally increases across a period. More protons and electrons in smaller volume.
- How does metallic character change across a period?
- Metallic character decreases across a period. Atoms lose electrons less easily with higher nuclear charge.
- What is the trend for atomic size across a period?
- Atomic size decreases across a period. Same as atomic radius due to increased nuclear charge.
- What is the trend for covalent radius across a period?
- Covalent radius decreases across a period. Same trend as atomic radius due to nuclear charge.
- What is the trend for electron affinity in noble gases?
- Noble gases have positive or zero electron affinity. Stable electron configurations resist gaining electrons.
- How does ionization energy change across a period?
- Ionization energy increases across a period. Higher nuclear charge makes it harder to remove electrons.
- What is the trend for ionic radius down a group?
- Ionic radius increases down a group. Additional electron shells increase ionic size.
- What is the trend for electronegativity down a group?
- Electronegativity decreases down a group. Increased distance reduces attraction for bonding electrons.
- How does ionization energy change down a group?
- Ionization energy decreases down a group. Increased shielding and distance reduce nuclear attraction.
- What causes the atomic radius to decrease across a period?
- Increased nuclear charge pulls electrons closer. More protons attract electrons more strongly.
- What is the trend for covalent radius down a group?
- Covalent radius increases down a group. Same trend as atomic radius due to electron shells.
- What is the trend for atomic radius down a group?
- Atomic radius increases down a group. Additional electron shells increase distance from nucleus.
- What is the trend for density down a group?
- Density generally increases down a group. More massive atoms with larger size pack more densely.
- What is the trend for ionic radius across a period?
- Ionic radius decreases across a period. Higher nuclear charge contracts electron clouds around ions.
- What is the trend for ionization energy in noble gases?
- High ionization energy due to full valence shell. Stable electron configurations require maximum energy to ionize.
- What is electron shielding?
- Inner electrons block outer electrons from nuclear charge. Core electrons reduce effective nuclear charge on outer electrons.
- Which element has the highest electronegativity?
- Fluorine. Highest nuclear charge with smallest atomic size.
- What trend is observed in melting points across a period?
- Melting points vary but generally increase across metals. More bonding electrons and smaller size strengthen bonds.
- Which element has the largest atomic radius?
- Cesium. Largest number of electron shells among all elements.
- What is the trend of metallic nature in the periodic table?
- Increases down a group, decreases across a period. Larger atoms lose electrons more easily than smaller ones.
- Which element has the smallest atomic radius?
- Helium. Highest nuclear charge with no shielding electrons.
- Which block of elements has the highest electronegativity?
- P-block. Contains fluorine and other highly electronegative nonmetals.
- What is the trend for atomic size down a group?
- Atomic size increases down a group. Same as atomic radius due to additional electron shells.
- What is the trend for reactivity in halogens down a group?
- Reactivity decreases down the group. Smaller size holds electrons more tightly.
- What is the trend for reactivity in alkali metals down a group?
- Reactivity increases down the group. Larger size makes valence electrons easier to lose.
- Which element has the highest ionization energy?
- Helium. Small size and high nuclear charge resist electron removal.