Ch. 6 Atoms, Ions, & Periodicity

Flashcards covering key concepts from Chapter 6: atoms, ions, isotopes, periodic table, and matter properties.

What is matter?

Anything that has mass and takes up space (has volume).

What does the Law of Conservation of Matter state?

Matter cannot be created or destroyed in a chemical reaction.

Where are protons and neutrons located in an atom?

In the nucleus of the atom.

What is an ion?

A charged particle that results from an atom gaining or losing electrons.

How do you determine the charge of an ion from the numbers of protons and electrons?

If there are more protons than electrons, the ion is positively charged; if there are more electrons than protons, it is negatively charged.

What is an element?

A substance made of a single type of atom.

What is a compound?

A substance made of two or more types of atoms chemically combined.

What is a pure substance?

Matter made of a single substance (elements or compounds).

What is a mixture?

Matter made of more than one substance that are physically combined.

What is a homogeneous mixture?

A mixture with uniform composition where components are not visibly different.

What is a heterogeneous mixture?

A mixture that is not uniform in composition; components are visibly different.

What are the three phases of matter?

Solid, liquid, and gas.

Do changes of state (phases) change the chemical identity of a substance?

No; phase changes do not change chemical composition.

What is an extensive property?

A property that depends on the amount of matter (e.g., mass, length).

What is an intensive property?

A property that does not depend on amount (e.g., density, temperature).

What is the mass number of an atom?

The sum of protons and neutrons in the nucleus.

What is the atomic number of an atom?

The number of protons (and, if neutral, the number of electrons).

What does the atomic mass on the periodic table represent?

A weighted average of the masses of all isotopes of that element.

What is a nuclide?

A specific nucleus defined by a particular number of protons and neutrons.

What is an isotope?

Nuclides that have the same number of protons but different numbers of neutrons.

How do you write the nuclide symbol for an atom with 15 protons and 16 neutrons?

31P (mass number 31, atomic number 15).

What is a period in the periodic table?

A horizontal row of elements.

What is a group in the periodic table?

A vertical column of elements.

What are representative elements?

Elements in groups 1-2 and 13-18 on the periodic table.

What are transition elements?

Elements in groups 3-12 (the transition metals).

What are alkali metals?

Group 1 elements; tend to lose 1 electron; very reactive; very soft.

What are alkaline earth metals?

Group 2 elements; tend to lose 2 electrons; reactive and soft.

What are halogens?

Group 17 elements; tend to gain 1 electron; very reactive nonmetals.

What are noble gases?

Group 18 elements; very nonreactive and typically gases.

What is a metalloid?

Elements with properties of both metals and nonmetals; semiconductors.

What are properties of metals?

Typically solid at room temperature, shiny, malleable, ductile, good conductors.

What are properties of nonmetals?

May be gas, liquid, or solid; brittle; poor conductors.