Atoms and the Periodic Table

Structure of the Atom and the Periodic Table

Scientists have developed a language of symbols to stand for elements.

• Chemical symbol: a notation of one or two letter that represent an element.

• First letter is ALWAYS a capital letter.

• Second (or third) letter is ALWAYS a lower case letter.

Multiple Choice

In chemical symbols, the first letter is always a ______ letter, and the second (or third) letter is always a _______ letter.

• capital, lower case

• lower case, lower case

• capital, capital

The Atom

• An element is matter that is composed of only one type of atom.

  Atoms have a positively charged nucleus surrounded by negatively charged electrons.

Multiple Choice

Atoms have a _________ charged nucleus.

• positively

• negatively

• neutral

Multiple Choice

Atoms are surrounded by _____________ charged electrons.

• positively

• negatively

• neutral

Subatomic particles

• Atoms are composed of even smaller particles (subatomic particles) called protons, neutrons, and electrons

• The small, positively charged, nucleus contains protons and neutrons.

Parts of an atom

• Proton: positively charged particle (1+) that are found in the nucleus of the atom.

• Neutron: particle with no charge that are found in the nucleus of the atom.

• Electron: negatively charged particle (1-) that are found in the electron cloud outside of the nucleus.

Multiple Choice

Protons are _________.

• positively charged particles that are found in the nucleus.

• negatively charged particles found in the electron cloud outside of the nucleus.

• particles with no charge that are found in the nucleus.

Multiple Choice

Electrons are _______.

• positively charged particles found within the nucleus.

• negatively charged particles found within the electron cloud outside of the nucleus.

• particles with no charge found within the nucleus.

Multiple Choice

Neutrons are _______.

• positively charged particles found within the nucleus

• negatively charged particles found in the electron cloud

• particle with no charge found within the nucleus

Multiple Select

Which two subatomic particles are found in the nucleus?

• Protons

• Electrons

• Neutrons

The Atomic Model

• By 1926, scientists developed the electron cloud model of the atom, which is the model accepted today.

• An electron cloud is the area around the nucleus of an atom where electrons are most likely found.

• Because an electron's mass is negligible compared to the nucleus and the electron is moving so quickly, it is impossible to describe the exact location in an atom at any given moment.

Open Ended

Identify the names, charges, and locations of three types of subatomic particles that make up an atom.

Open Ended

Identify the chemical symbols for the elements carbon, aluminum, hydrogen, oxygen, and sodium.

Organizing Elements

• In the late 1800s, a Russian chemist named Dmitri Mendeleev presented a way to organize all known elements.

• Mendeleev was able to predict probable properties and atomic masses of missing elements based on his arrangement of the periodic table.

• In the modern periodic table, the elements are arranged by increasing atomic number and by periodic changes in physical and chemical properties.

Multiple Choice

Elements are arranged by increasing _________.

• atomic mass

• atomic number

• they are arranged randomly.

• Modern table consists of elements tiles that contain information about each element - element name, symbol, atomic number, and atomic mass.

• Elements are organized based on similiarites in their physical and chemical properties.

• Columns of elements are called groups. Elements in the same group have similar chemical properties.

• Rows of elements are called periods. Atomic number increasing across a period.

Multiple Choice

Elements in the same group have similar physical and chemical properties.

• True

• False

Elements in the same group have the same number of electrons in their outermost energy level.

• These electrons are called valence electrons.

• The number of valence electrons determine the chemical properties of each element.

Multiple Choice

Valence electrons are _______.

• located the outermost energy level.

• located in the inner most energy level.

Multiple Choice

Elements in the same group have the same number of valence electrons.

• True

• False

Regions of the Periodic Table

• Metals (left side of table)

• Nonmetals (right side of table)

• Metalloids (exhibit both metal and nonmetal properties)

• Groups 1 - 18

• Periods 1-7

Open Ended

Use the periodic table to find the name, atomic number, and atomic mass of the following elements: N, P, Al.

Open Ended

Provide the symbol, the group number, and the period of each of the following elements: Nitrogen, Sodium, Iodine.