2: Atoms and the Periodic Table

Flashcards covering Chapter 2 topics including the periodic table, types of elements, groups and periods, atomic structure, isotopes, atomic weight, energy levels, sublevels, orbitals, electron configuration, valence electrons, and periodic trends (atomic radii and ionization energy).

What are the three types of elements that make up the periodic table?

Metals, Nonmetals, and Metalloids

How are elements in the same vertical column of the periodic table categorized?

They are in the same 'Group'.

How are elements in the same horizontal row of the periodic table categorized?

They are in the same 'Period'.

Name four special groups of elements on the periodic table.

Alkali metals, Alkaline Earth metals, Halogens, Noble gases

Name two special periods of elements on the periodic table.

Lanthanides and Actinides

How is the periodic table arranged?

In increasing atomic number.

What is an atom?

The smallest unit of an element that retains the chemical properties of that element.

In a neutral atom, what is the relationship between the number of protons and electrons?

The number of protons must equal the number of electrons.

Which subatomic particles are approximately the same size?

Neutrons and protons.

What does the atomic number represent?

The number of protons (and the number of electrons in a neutral atom).

What does the mass number represent?

The sum of the number of protons and neutrons.

What are isotopes?

Atoms with the same number of protons but different numbers of neutrons.

What is atomic weight?

The weighted average of the masses of the naturally occurring isotopes of an element.

How are principal energy levels divided?

Into sublevels designated by the letters s, p, d, and f.

What is an orbital?

A region of space that can hold two electrons.

Which electrons are held most strongly by the nucleus and have the least amount of energy?

Electrons in the first shell, closest to the nucleus.

How many orbitals and maximum electrons can an 's' sublevel have?

1 orbital, 2 electrons.

How many orbitals and maximum electrons can a 'p' sublevel have?

3 orbitals, 6 electrons.

How many orbitals and maximum electrons can a 'd' sublevel have?

5 orbitals, 10 electrons.

How many orbitals and maximum electrons can an 'f' sublevel have?

7 orbitals, 14 electrons.

What is the maximum number of electrons that can be in the 3rd principal energy level?

18 electrons (3s: 2, 3p: 6, 3d: 10).

What does the Pauli exclusion principle state?

An atomic orbital can hold a maximum of two electrons, and they must have opposite spins.

What are valence electrons?

The electrons in the outermost (highest) principal energy level of an atom, actively involved in forming bonds.

What are core electrons?

The inner electrons of an atom, not involved in bonding.

What characteristic do atoms in the same group on the periodic table share regarding electrons?

They have the same number of valence electrons.

When drawing electron-dot symbols, how many dots are placed on each side before pairing?

One dot is placed on each side of the symbol before pairing begins.

What is the trend for atomic radii (AR) across a period?

Atomic radii generally decrease across a period (left to right).

What is the trend for atomic radii (AR) down a group?

Atomic radii generally increase down a group (top to bottom).

What is ionization energy (IE)?

The energy required to remove an electron from an individual atom in the gas phase.

What kind of ionization energies do metals typically have?

Low ionization energies.

What is the trend for ionization energy (IE) across a period?

Ionization energy generally increases across a period (left to right).

What is the trend for ionization energy (IE) down a group?

Ionization energy generally decreases down a group (top to bottom).