21

What is the atomic number of the element with the symbol 'Sc'?

• 19

• 20

• 21

• 22

Which of the following elements has 21 protons in its nucleus?

• Calcium

• Scandium

• Titanium

• Vanadium

In the periodic table, which group does the element with atomic number 21 belong to?

• Group 1

• Group 2

• Group 3

• Group 4

What is the electron configuration of the element with atomic number 21?

Tags

NGSS.HS-PS1-1

Which of the following isotopes has 21 neutrons?

What is the mass number of an atom with 21 protons and 24 neutrons?

• 45

• 44

• 43

• 42

Which of the following elements is a transition metal with atomic number 21?

• Zinc

• Copper

• Scandium

• Iron

What is the most common oxidation state of the element with atomic number 21?

• +1

• +2

• +3

• +4

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following compounds contains the element with atomic number 21?

Tags

NGSS.MS-PS1-1

What is the melting point of the element with atomic number 21?

• 1541 °C

• 1539 °C

• 1519 °C

• 1529 °C

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4