Patterns in the periodic table

What is the modern periodic table arranged by?

Increasing atomic number.

What is a period on the periodic table?

A horizontal row of elements.

What is a group (or family) on the periodic table?

A vertical column of elements with similar properties.

What are alkali metals?

Group 1 elements, very reactive metals.

What are alkaline earth metals?

Group 2 elements, reactive metals but less so than alkali metals.

What are transition metals?

Elements in the center block of the periodic table, often used in construction and electronics.

What are halogens (or halides)?

Group 17 non-metals, very reactive, especially with metals.

What are noble gases?

Group 18 gases that are non-reactive due to full valence shells.

What are inner transition metals?

The elements in the two rows below the main body of the periodic table (lanthanides and actinides).

What are main group elements?

Elements not part of the transition metals (includes groups 1, 2, and 13–18).

What charge does an electron carry, and what is its mass?

Negative charge; almost no mass.

Where are protons and neutrons found, and what are their charges?

In the nucleus; protons are positive, neutrons have no charge.

What is the atomic number?

The number of protons in an atom.

How many electrons are in a neutral atom?

The same number as protons.

What is the atomic mass number?

The number of protons plus neutrons.

What is an isotope?

Atoms of the same element with different numbers of neutrons.

What is the Bohr-Rutherford model?

A diagram that shows protons, neutrons, and electrons in orbits around the nucleus.

How many electrons fit in the first three orbits?

2 in the first, 8 in the second, 8 in the third.

What are valence electrons?

Electrons in the outermost orbit.

What is a Lewis Dot Diagram?

A quick way to show valence electrons around an element’s symbol.

How do you draw a Lewis Dot Diagram?

1.Write the element symbol

2.Find the number of valence electrons

3.Place one dot on each side, then pair if needed

4.Max of two per side, eight total