The Periodic Table and Some Atomic Properties

Flashcards about the periodic table and its properties based on lecture notes.

How are elements arranged on the periodic table?

The arrangement of elements in order of increasing atomic number (Z).

What are groups or families in the periodic table?

Vertical columns numbered 1 to 18; elements in the same group have similar characteristics.

What are periods in the periodic table?

Horizontal rows numbered 1 to 7; each period contains elements with electrons in the same outer shell.

What is the state of metals at room temperature?

They are solids at room temperature, except mercury, which is a liquid.

What are Noble Gases?

Group 8A (also called group 18 or 0); electron configuration is 1s2 for helium and ns2 np6 for others.

Why are Noble Gases unreactive?

Their outer s and p electron configurations are filled, making them unreactive.

What are transition metals?

d-block elements, designated in the B groups of the periodic table.

What characterizes transition metals electronically?

Electrons are being added to d orbitals.

What are the characteristic properties of transition elements?

High electrical and thermal conductivity, high melting point, malleable, high tensile strength, and ductile.

What is atomic size or radius?

Half the distance of closest approach between two identical atoms.

What happens to atomic size when moving left to right across a period?

Atomic size decreases due to increase in core charge (Zeff).

What happens to atomic size when moving top to bottom down a group?

Atomic size increases due to an increase in the number of shells.

Why is a cation smaller than the atom from which it is formed?

A cation is smaller because the excess of protons draws the outer electrons closer to the nucleus.

Why is an anion larger than the atom from which it is formed?

An anion is larger because there is more repulsion between electrons.

What is ionization energy?

The amount of energy it takes to detach one electron from a gas neutral atom.

What happens to ionization energy when moving from left to right across a period?

Ionization energy increases because attraction is greater between the outer shell electrons and the nucleus.

What happens to ionization energy when moving from top to bottom down a group?

Ionization energy decreases because the attraction is weaker between the outer shell electrons and the nucleus due to increasing atom size.

What is electronegativity?

The ability of an atom to attract a pair of electrons towards itself in a chemical bond.

What happens to electronegativity when moving from left to right across a period?

Electronegativity increases due to a greater attraction of the outer shell electrons to the nucleus.

What happens to electronegativity when moving from top to bottom down a group?

Electronegativity decreases because the electrons are further from the nucleus, resulting in a weaker attraction.

What is endothermic energy?

Absorbs energy (given a + sign).

What is exothermic energy?

Releases energy (given a - sign).

Is ionization energy endothermic or exothermic?

Energy is added to the atom to remove the electron.

Which element has the highest electronegativity?

Fluorine (4.0)

How does nuclear charge affect ionization energy?

Nuclear charge increases attraction of valence electrons, increasing IE.

How does the shielding effect affect ionization energy?

Greater distance from the nucleus decreases IE due to shielding effect.

Which group is commonly known as noble gases?

Group 8A

What is the trend of atomic size from top to bottom in a group?

Increases

Which elements have electron configurations that end in ns2np5?

Halogens