5.4 Patterns and the Periodic Table

Chemistry SNC2D5

What are elements?

Pure substances that cannot be chemically broken down into smaller substances; they are the basic unit of matter.

What is the primary characteristic of metals in the Periodic Table?

Metals are shiny, solid, and conduct electricity.

What are non-metals typically like?

Non-metals are usually gaseous, not conductive, and highly variable.

What separates metals and non-metals on the Periodic Table?

A staircase line that runs from boron (B) to astatine (At).

What are metalloids?

Elements that have characteristics of both metals and non-metals.

What are vertical columns in the Periodic Table called?

Families or groups.

What are the four common groups in the Periodic Table?

Alkali metals (Group 1), Alkaline earth metals (Group 2), Halogens (Group 17), Noble gases (Group 18).

What are alkali metals known for?

They are soft, shiny, and very reactive.

How do alkaline earth metals compare to alkali metals?

Alkaline earth metals are harder, still shiny, and less reactive than alkali metals.

What is the reactivity of halogens?

Halogens are highly reactive and vary in structure and form.

What is a characteristic of noble gases?

They are all gaseous, highly stable, and rarely react.

What are periods in the Periodic Table?

Rows across the Periodic Table where each period adds another orbital for electrons.

What is the nucleus of an atom?

The solid and dense central core containing protons and neutrons.

What particles are found in the nucleus?

Protons (positively charged) and neutrons (neutral).

What are electrons and where are they located?

Electrons are negatively charged particles that orbit the nucleus in electron shells.

What does the atomic number represent?

The number of protons in an element.

What does the mass number indicate?

The average number of protons and neutrons in a sample of the element.

What is the atomic mass?

The rounded mass number to the nearest whole number, showing the number of protons and neutrons.

What are Bohr-Rutherford diagrams used for?

To represent the structure and electron arrangement of atoms.

What is the maximum number of electrons the first period can hold?

Up to 2 electrons.

How many electrons can the second, third, and fourth periods hold?

Each can hold up to 8 electrons.

What dictates an element's reactivity?

The number of electrons in the outer (valence) orbital.

What is the octet rule?

Atoms desire stability by having their valence shell filled with 8 electrons.

How do atoms achieve a filled valence shell?

Through chemical reactions that involve the transfer or sharing of electrons.