Physics Atom Structure

The smallest unit of ordinary matter that forms a chemical element is the definition for _________.

• compound
• molecule
• ion
• atom

A substance whose atom all have the same number of protons or atomic number is an (a)   .

During a science class, James learned that an element is ______

• a mixture of different atoms

• a compound made of two or more elements

• a pure substance consisting of one type of atom

• a type of molecule that can exist independently

There are ______ number of elements in the periodic table.

• 115
• 120
• 118
• 100

What is a compound?

• A compound is a substance made up of two or more different elements that are chemically bonded together.
• A compound is a type of chemical reaction that occurs between elements.
• A compound is a mixture of two or more substances that retain their individual properties.
• A compound is a single element that cannot be broken down.

Examples of compounds found in everyday life?

• NaCl=

  Sodium Chloride,

  Table salt

• Mg

  Magnesium

• NaOCl =

  Sodium hypochlorite,

  Bleach

• NaHCO_3,

  Sodium Bicarbonate,

  Baking Soda

• MgSO₄=

  Magnesium Sulphate,

  Epsom Salt

STRUCTURE OF THE ATOM

Atoms are made up of the three subatomic particles________, ________ and_________.

• protons, neutrons, electrons
• protons, muons, neutrinos
• neutrons, electrons, quarks
• protons, electrons, positrons

What charge is an atom?

• An atom has a positive charge.
• An atom has a negative charge.
• An atom has a fluctuating charge.
• An atom has no charge (neutral).

Answer explanation

Number of electrons = Number of protons

(negative charge) = (positive charge)

STRUCTURE OF THE ATOM

This part of the atom is in the middle and it contains only the protons and neutrons.

• nucleus
• electron
• proton cloud
• valence shell

STRUCTURE OF THE ATOM

What charge is the nucleus of the atom?

• The nucleus of the atom is neutrally charged.
• The nucleus of the atom is positively charged.
• The nucleus of the atom has no charge.
• The nucleus of the atom is negatively charged.

Answer explanation

Nucleus = protons + Neutrons

(+ve charge comes from protons)