Chemistry B CP

The atomic number is always equal to the number of __________ inside an atom

• protons

• neutrons

• electrons

• positrons

Which statement best describes Lithium's atomic mass of 6.941

• Every atom of Li has a mass of 6.941

• The atomic mass must be rounded off to know how much each atom of lithium weighs, regardless of which isotope of Li.

• The chances of one atom of lithium weighing 6.941 is zero because this is a weighted average of different isotopes of lithium.

• none of these

An atom with 19 protons and 20 neutrons has a mass number of ________.

• 1

• 19

• 29

• 39

• none of these

The half-life of a radioactive isotope is _________.

• Half the time required for the complete decay of a radioactive isotope.

• The amount of time required for 50% of the original number of radioactive atoms to decay

• The amount of time it takes for 25% of a radioactive isotope to remain.

• The amount of time it takes to reduce the radioactivity by 100%

• none of these

Tags

NGSS.HS-PS1-8

This shows a table salt molecule. What is it?

• compound

• element

• mixture

Tags

NGSS.MS-PS1-1

How many valence electrons does Potassium Have?

• 1 Valence electron

• 2 Valence electron

• 3 Valence electron

• 4 Valence electron

• 5 Valence electron

Which item on this element square is the chemical symbol?

• Copper

• 29

• Cu

• 63.546

Which of these samples shown best represents an element?

• A

• B

• C

• D

Tags

NGSS.MS-PS1-1

How many valence electrons does Silicon Have?

• 1 Valence electron

• 2 Valence electron

• 3 Valence electron

• 4 Valence electron

• 5 Valence electron

Tags

NGSS.MS-PS1-1

Made up of only 1 type of atom

• Compound

• Molecule

• Element

• Mixture

Tags

NGSS.MS-PS1-1