Periodic Trends and Ionization in AP Chemistry

Who created the original Periodic Table of Elements?

Dmitri Mendeleev

How is the modern Periodic Table organized?

By atomic number

What are the columns in the Periodic Table called?

Groups

What are the rows in the Periodic Table called?

Periods

What are the general properties of metals?

Solid at room temperature (except mercury), shiny, malleable, ductile, high melting points, and excellent conductors of heat and electricity.

What are non-metals typically like at room temperature?

They can be solid, liquid, or gas, are dull, lack luster, and are poor conductors.

What are metalloids?

Elements that have properties of both metals and non-metals and are solid at room temperature.

What are allotropes?

Different molecular forms of the same element that have different properties.

What group of elements are known as halogens?

Group 17, highly reactive nonmetals.

What group contains the noble gases?

Group 18

What is Coulombic attraction?

The attractive force between opposite charges (e.g., electron-proton interaction).

What trend occurs in atomic radius across a period?

Atomic radius decreases due to increased Coulombic attraction.

What trend occurs in atomic radius down a group?

Atomic radius increases due to more occupied shells.

What is the first ionization energy?

The amount of energy needed to remove an electron from a gaseous atom to form a positive ion.

How does ionization energy change across a period?

Ionization energy increases due to greater effective nuclear charge (Zeff).

How does ionization energy change down a group?

Ionization energy decreases due to increased distance and shielding.

What is the ionic radius of a positive ion compared to its atomic radius?

The ionic radius of a positive ion is smaller than the atomic radius of the element.

What is the ionic radius of a negative ion compared to its atomic radius?

The ionic radius of a negative ion is larger than the atomic radius of the element.

What is electron affinity?

The energy change that occurs when an electron is added to a gaseous atom to form a negative ion.

What does a negative electron affinity value indicate?

It releases energy (exothermic) and indicates a strong likelihood of gaining an electron.

What does a positive electron affinity value indicate?

It requires energy (endothermic) and indicates a low likelihood of gaining an electron.

What is effective nuclear charge (Zeff)?

It is approximated as Zeff = Z - S, where Z is the atomic number and S is the shielding constant.

How does ionic size change with increasing nuclear charge?

Ionic size decreases with an increasing nuclear charge.

What happens to the size of ions as you go down a column?

Ions increase in size due to increasing principal energy levels (n).

What is the relationship between the number of protons and electron attraction?

More protons result in greater attraction towards the nucleus.