Exam (elaborations) Honors Chemistry

Honors Chemistry: Periodic Trends with comprehensive Questions
and Answers

Atomic radius✔️✔️Half the distance between two identically bonded atoms



Ionic radius✔️✔️The radii of the most commonly found ion of the element.



First Ionization Energy✔️✔️The energy required to remove one electron from a neutral atom of an
element.


Electron Affinity✔️✔️The energy change that occurs when an electron is acquired by a neutral
atom


Number of Valence Electrons✔️✔️The electrons that are available to be lost, gained, or shared in
the formation of chemical compounds.


Melting point✔️✔️The temperature at which a solid turns into a liquid.



Thermal Conductivity✔️✔️The ability of a substance to conduct heat.



Electronegativity✔️✔️The ability of an atom to pull the bonded electrons to itself in a chemical
compound.


Trend From Left to Right Across a Period (Atomic Radius)✔️✔️Decrease



Trend From Left to Right Across a Period (Ionic Radius)✔️✔️Decreases across the metals and
then gets much larger at the nonmetals and then decreases again.


Trend From Left to Right Across a Period (First Ionization Energy)✔️✔️Increases

, Trend From Left to Right Across a Period (Electron Affinity)✔️✔️Increases



Trend From Left to Right Across a Period (Number of Valance Electrons)✔️✔️Increases



Trend From Left to Right Across a Period (Melting Point)✔️✔️Decrease



Trend From Left to Right Across a Period (Thermal Conductivity)✔️✔️Decreases



Trend From Left to Right Across a Period (Electronegativity)✔️✔️Increases



Periodic Trends✔️✔️A pattern exhibited by the chemical or physical characteristics of the
elements on the periodic table. Increases across and decreases down → IE, EA, EN - Decreases
across and increases down → AR, IR (sort of),MP, TC


How is ionization energy related to how easily an electron can be lost from an atom?✔️✔️The
easier it is to lose an electron the smaller the amount of energy needed to remove it (smaller
ionization energy).


What happens to the amount of positive charge in the nucleus as you go from left to right across
a period?✔️✔️The amount of positive charge increases as the number of protons increase from left
to right across a period.


How would this account for the trend you discovered in atomic radius?✔️✔️Electrons are held
more tightly and are pulled in closer by the nucleus as the number of protons increases within a
level.


How would this account for the trend you discovered in the first ionization energy?✔️✔️Because
of the additional protons, electrons are held more tightly by the nucleus which increases the
amount of energy (ionization energy) needed to remove them.