5.3 Atomic number and mass number

What does the atomic number of an element represent?

• The number of neutrons in the nucleus

• The number of protons in the nucleus

• The total number of protons and neutrons in the nucleus

• The number of electrons in the outer shell

Tags

NGSS.MS-PS1-1

If the atomic number of carbon is 6, how many protons does a carbon atom have?

• 4

• 6

• 8

• 12

Tags

NGSS.MS-PS1-1

Why is it important to remember the atomic number as the smaller of the two numbers given with each element on the periodic table?

• Because it represents the total number of particles in an atom

• Because it represents the number of electrons

• Because it is usually the top number on the element's periodic table box

• Because it determines the element's color on the periodic table

Tags

NGSS.MS-PS1-1

What can you conclude about an element that contains six protons?

• It is always carbon

• It is always oxygen

• It is always nitrogen

• It is always helium

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NGSS.MS-PS1-1

What does the atomic number of an element tell you about the atom?

• The number of neutrons in the atom

• The number of protons in the atom

• The total mass of the atom

• The number of molecules in the atom

Tags

NGSS.MS-PS1-1

If an atom has an atomic number of 6, how many electrons does it have assuming the atom is neutral?

• 4

• 6

• 8

• 12

Tags

NGSS.MS-PS1-1

What is formed when an atom loses electrons and becomes positively charged?

• A molecule

• A neutron

• An ion

• A compound

Which of the following statements is true regarding ions?

• An ion with a (+) sign has gained electrons and is negatively charged.

• An ion with a (-) sign has lost electrons and is positively charged.

• An ion with a (+) sign has lost electrons and is positively charged.

• An ion with a (-) sign has gained protons and is negatively charged.

Tags

NGSS.MS-PS1-5

What is the atomic number of hydrogen?

• 0

• 1

• 2

• 3

Tags

NGSS.MS-PS1-1

What happens to an atom when the number of electrons is changed?

• The atom becomes a noble gas.

• The atom does not change its properties.

• The properties of the atom change and it can become positively or negatively charged.

• The atom becomes a halogen.