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Atomic Structure

Modern Theory: The

Electron Cloud Model

What is the structure of an atom?

atom is made up of 3 subatomic particles

• protons and neutrons- inside the nucleus

• electron-outside the nucleus

• nucleus-small dense center of an atom

• nucleus- the atomic mass is concentrated

​this is Bohr model of atom

that places the electrons by energy levels

Multiple Choice

The negatively charge particle in an atom is called

• electron

• proton

• neutron

Multiple Choice

Atom is the smallest particle of matter. However, there are 3 particles inside of it that are called subatomic particles. True or False?

• True

• False

• I am not sure

Multiple Choice

The small but dense center of an atom is called

• cloud

• center

• nucleus

Multiple Select

Which pair correctly describe the locations of subatomic particles in an atom?

• electron-inside the nucleus

• proton-inside the nucleus

• neutron-inside the nucleus

• electron-outside the nucleus

Each Element = One Atom

• atomic number (whole number) = to number of protons

• mass number (rounded atomic mass) = the number of protons + number of neutrons

• in a neutral atom, the number of protons equals the number of electrons

• all elements in the periodic table are in ground state (neutral)

• therefore, each atom has same number of protons and electrons which is the same as the atomic number

The Periodic Table

• made of different elements arranged in rows and columns

• each element equals to ONE atom

• an element is identified by its chemical symbol

Atomic Mass or Mass Number

• mass number= the # of protons and neutrons in the nuclues of an atom

• What is the mass of an atom(atomic mass) as shown in the picture?

• Count the number of protons and neutrons=7

• How many protons? 3

• The element # 3 in the PTable

An Atom of Oxygen

• each atom in the PTable is in the ground state

• it is neutral, meaning no charge

• # of protons=# of electrons

What is in the box?

• In an atom of oxygen element

• atomic number= 8

• # protoms = 8

• # of electrons = 8

• atomic number= # of protons = # of electrons, because it is neutral

Atomic Number or # of protons determine the identity of an atom(its element name)

​

Multiple Select

In a neutral atom, atomic number is equals to the number of

• protons in an atom

• electrons in an atom

• neutrons in an atom

• atomic mass of an atom

Multiple Choice

An atom has 19 protons. What is its element name?

• potassium (Po)

• potassium (K)

• neon (N)

• fluorine(F)

Multiple Choice

The atomic number of an element is fixed and it is ALWAYS equal to the element's number of protons. True or False?

• true

• false

• sometimes

Multiple Choice

An atom has 20 protons, 20 electrons, and 20 neutrons. What is the name of the atom?

• potassium (K)

• calcium(Ca)

• neon (N)

• sodium (Na)

Multiple Choice

What is the mass of this atom as shown?

• 6

• 8

• 12

• cannot be determined

Multiple Choice

As shown in the element box information, lithium has ____number of neutrons.

• 3

• 4

• 6

• 7

Multiple Choice

What is an atom?

• The largest unit of matter.

• The smallest unit of matter.

• A banana

Multiple Choice

What is found in the nucleus of an atom?

• Protons

• Electrons

• Protons and Electrons

• Protons and Neutrons

Multiple Choice

What is an atomic number?

• Number of electrons an atom has

• Number of neutrons an atom has

• Number of protons an atom has

Multiple Choice

What element has only one electron?

• Helium

• Carbon

• Lithium

• Hydrogen

Multiple Choice

mass number

• number of neutrons in an atom

• number of protons in an atom

• number of neutrons and protons in an atom

• number of protons and electrons in an atom

• number of neutrons, protons and electrons in an atom

Multiple Choice

From the diagram, which particles are indicated with the arrow?

• electrons and protons

• protons and neutrons

• electrons and neutrons

• photons and nucleons

Multiple Choice

These particles orbit around the nucleus of an atom.  What are they called?

• electrons
• protons
• neutrons
• photons

Multiple Choice

What Greek word did electron originate from?

• electrum
• amperes
• amber
• calefie

Multiple Choice

Who invented the Atomic Theory?

• Dalton
• Edward
• Einstein
• Darwin

Multiple Choice

How can atoms be neutral if they contain charged particles?

• Every atom has the same number of protons and electrons
• Every atom has neutrons
• Every atom has different numbers of protons and electrons
• Every atom has electrons in the nucleus