Atoms and Periodic Table

An element has an atomic number of 20. This means it has:

• 20 atoms in it.

• 20 protons.

• an atomic mass of 20.

• 20 neutrons.

Protons and electrons:

• have the same mass

• are both found in the nucleus.

• have opposite charges.

• are added together to find the atomic mass.

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Scandium atoms have an atomic number of 21 and atomic mass of 45. What is NOT true about Scandium atoms?

• It has 24 neutrons.

• A neutral atoms has 21 protons and 21 electrons.

• It has 21 neutrons.

• It has 21 protons.

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What is the atomic number of the atom shown in the picture?

• 13

• 14

• 1

• 27

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What is true about the Periodic Table?

• Elements in the same Family have the same number of protons.

• Elements in the same Family have similar chemical properties.

• Elements in the same Family are shown in the same row.

• Elements in the same Family have the same number of electrons.

Which statement is NOT true about atoms?

• Protons and neutrons are both found in the nucleus.

• Protons and neutrons are added together to find the atomic mass.

• Protons and electrons are both found in the nucleus.

• Atoms are identified by its number of protons.

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NGSS.MS-PS1-1

What is NOT true about Iron?

• Fe is the chemical symbol.

• The atomic mass is 26.

• The atomic number is 26.

• It has 30 neutrons.

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Where is the concentration of mass in an atom?

• The nucleus

• The electron cloud

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Which element is most likely to be a semi-conductor?

• B

• F

• Li

• H

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An atom is neutral if:

• it has the same number of protons and neutrons.

• it has the same number of protons and electrons.

• it has an even number of valence electrons.

• it has the same number of electrons and neutrons.