chapter 11

Question 2

What information does the periodic table show?

Answer 2

• Atomic number
• Atomic mass
• Chemical symbol
• Chemical name
• State of matter
• Energy levels of electrons

The periodic table is organized by increasing atomic number, which corresponds to the number of protons in the nucleus.

Question 3

How are the elements organized in the periodic table?

Answer 3

• Increasing atomic number
• Rows (periods) increase from left to right
• Columns (families/groups) contain elements with similar chemical properties

The periodic table divides elements into three main groups: metals, nonmetals, and metalloids.

Question 4

What are the three main groups of elements in the periodic table?

Answer 4

• Metals
• Nonmetals
• Metalloids

Metals are located on the left and center, nonmetals on the far right, and metalloids along a zigzag line.

Question 5

What is a chemical bond?

Answer 5

A force that holds 2 or more atoms together

Atoms will chemically combine to form compounds.

Question 6

In an uncharged atom, the number of protons equals the number of _______.

Answer 6

electrons

The exact location of electrons is not known; they exist in regions around the nucleus.

Question 7

What are energy levels in relation to electrons?

Answer 7

• Areas around the nucleus
• Lowest energy levels are closest to the nucleus
• 1st energy level holds 2 electrons
• 2nd energy level holds up to 8 electrons (except helium)

Electrons have different amounts of energy based on their distance from the nucleus.

Question 8

What are valence electrons?

Answer 8

The outermost electrons involved in chemical bonding

Valence electrons have the most energy and determine the type and number of bonds an atom can form.

Question 9

How can the number of valence electrons be determined?

Answer 9

By its location on the periodic table

This method works for columns 1, 2, 13, 14, 15, 16, 17, 18; transition metals do not follow this pattern.

Question 10

What is an electron dot diagram?

Answer 10

A model that shows the valence electrons of an element

It uses the chemical symbol and a pattern of dots to predict the type and number of bonds an element will make.

Question 11

What is a compound?

Answer 11

A pure substance made up of 2 or more different elements

Compounds have different physical and chemical properties from the elements that make them up.

Question 12

What is a covalent bond?

Answer 12

A chemical bond formed when 2 atoms share 1 or more pairs of valence electrons

Covalent bonds result in stable covalent compounds that try to achieve the same arrangement as noble gases.

Question 13

What are the properties of covalent compounds?

Answer 13

• Low melting points
• Low boiling points
• Most are gases or liquids at room temperature
• Poor conductors of heat and electricity
• Form molecules

Molecules are groups of atoms held together by covalent bonding that act as independent units.

Question 14

What is a polar molecule?

Answer 14

A molecule with a slightly positive end and a slightly negative end

This occurs when electrons are pulled closer to one of the elements in a covalent bond, like in water.

Question 15

What is an ion?

Answer 15

An atom that is not electrically neutral because it has lost or gained valence electrons

Ions can be positive (lost electrons) or negative (gained electrons).

Question 16

What happens when an atom loses valence electrons?

Answer 16

It becomes a positive ion

Metals on the far left of the periodic table tend to lose valence electrons to become stable.

Question 17

What happens when an atom gains valence electrons?

Answer 17

It becomes a negative ion

Nonmetal atoms can gain electrons from metals or share electrons in covalent bonds.

Question 18

What is an ionic bond?

Answer 18

The attraction between positively and negatively charged ions in an ionic compound

Ionic bonds form when valence electrons transfer from one atom to another.

Question 19

What are the properties of ionic compounds?

Answer 19

• Solid and brittle at room temperature
• High melting and boiling points
• Tend to dissolve in water
• Conduct electricity when dissolved

Ionic compounds are formed from the transfer of electrons between metals and nonmetals.

Question 20

What is a metallic bond?

Answer 20

A bond formed when many metal atoms share their pooled valence electrons

This results in positive metal ions in a sea of negative electrons, allowing for conductivity and malleability.