AP Chem #4 - Ch 7-8

As the number of known elements increased, scientist began classifying them and organizing them. In 1869, Mendeleev noticed a pattern when elements are arranged by ___.

• increasing atomic weight

• decreasing atomic weight

• increasing atomic number

• decreasing atomic number

Two years after Rutherford's nuclear model of an atom was published, Henry Moseley developed the concept of ___ leading to the modern periodic table.

• atomic number

• atomic weight

• average atomic mass

• atomic radius

Many properties depend on electron config and their attractions. One measurement is the Effective Nuclear Charge. If sodium has the config of [Ne]3s¹, what is the effective nuclear charge?

• 1+

• 2+

• 3+

• 1-

Why does the attraction of a valence electron to the nucleus decrease as the atomic number increases?

• Increased shielding effect by increasing core e-

• Decreasing atomic radius increases electronegativity

• Increasing atomic number implies increased number of protons

• Decreasing ionization energy implies electrons are removed more easily

Within each group, bonding atomic radius tends to ___ from top to bottom.

• increase

• decrease

• stay constant

Within each period, bonding atomic radius tends to ___ from left to right.

• increase

• decrease

• stay constant

Ionization energy of an atom is the minimum energy required to remove an electron.

The first ionization energy, IE₁, generally ___ as we move left to right across a period.

• increases

• decreases

• stays constant

Ionization energy of an atom is the minimum energy required to remove an electron.

The first ionization energy, IE₁, generally ___ as we move down a group.

• increase

• decrease

• stays constant

The energy change that occurs when an electron is added to a gaseous atom is called the electron affinity.

Which group on the periodic table would have the highest electron affinity?

• The halogens

• The noble gases

• The alkali metals

• The alkaline-earth metals

A ___ is a group of elements that have full s and p subshells and very large first ionization energies. What is this group called?

• Noble Gases

• Halogens

• Alkali metals

• Alkaline-Earth metals