Periodic Trends Contrast Matrix:
Definition of Atomic Radius:
Definition of Ionization Energy:
Trends: As you go across a period, atomic radius Trends: As you go across a period, ionization
________________. As you go down a group, energy ________________. As you go down a
atomic radius _________________.
group, ionization energy _________________.
Explanation of why this trend is observed:
Explanation of why this trend is observed:
Definition of Electronegativity:
Trends: As you go across a period,
electronegativity _____________. As you go
down a group, electronegativity ____________.
Explanation of why this trend is observed:
Arrows showing how trend increases:
Arrows showing how trend increases:
Arrows showing how trend increases:
Periodic Trends Contrast Matrix Answers:
Definition of Atomic Radius:
The atomic radius of an element is half of the distance
between the centers of two atoms of that element that are just
touching each other
Trends: As you go across a period, atomic radius decreases.
As you go down a group, atomic radius increases.
Explanation of why this trend is observed:
Increasing the number of protons increases the nuclear charge
in the nucleus in the same principal energy level (n). This
increased charge increases attraction of electrons to the
nucleus. As you go down a group, adding another principal
energy level results in valence electrons being further from
the nucleus.
Arrows showing how trend increases:
Definition of Ionization Energy:
The ionization energy, is the energy required to completely
remove an electron from a gaseous atom or ion. The closer
and more tightly bound an electron is to the nucleus, the more
difficult it will be to remove, and the higher its ionization
energy will be.
Trends: As you go across a period, ionization energy
increases. As you go down a group, ionization energy
decreases.
Explanation of why this trend is observed: As you go across
a period, the increased nuclear charge decreases the atomic
nucleus, making it more difficult to remove an electron. As
you go down a group, the ionization energy decreases because
the addition of a principal energy level results in the electrons
becoming further from the nucleus: decreased attraction
makes it easier to remove an electron.
Arrows showing how trend increases:
Definition of Electronegativity:
Electronegativity is a measure of the attraction of an atom for
the electrons in a chemical bond. The higher the
electronegativity of an atom, the greater its attraction for
bonding electrons.
Trends: As you go across a period, electronegativity
increases. As you go down a group, electronegativity
decreases.
Explanation of why this trend is observed: Increasing
nuclear charge increases attractions to electrons (across a
period); as you go down a group, there is an added principal
energy level (electrons are further from the nucleus), which
makes the electron further from the nucleus, making it more
difficult for the atom to attract electrons.
Arrows showing how trend increases: