The video tutorial explains the periodic table, focusing on atomic and mass numbers, and how they relate to elements. It introduces isotopes, their stability, and how to write isotope notation in hyphen and nuclear forms. The concept of average atomic mass is also covered, highlighting its role in identifying the most common isotopes of elements.

What does the atomic number of an element represent?

• Number of electrons

• Number of neutrons

• Total mass of the atom

• Number of protons

Who was responsible for organizing the periodic table by atomic numbers?

• Niels Bohr

• Henry Moseley

• Albert Einstein

• Isaac Newton

What is the mass number of an atom?

• Sum of protons and electrons

• Sum of neutrons and electrons

• Sum of protons and neutrons

• Number of protons only

How can you calculate the number of neutrons in an atom?

• Mass number divided by two

• Add protons and electrons

• Subtract electrons from protons

• Subtract the number of protons from the mass number

What defines an isotope of an element?

• Different number of electrons

• Different number of neutrons

• Different number of protons

• Different atomic number

Tags

NGSS.MS-PS1-5

Which ratio tends to be most stable in isotopes with atomic numbers less than 20?

• Two protons to one neutron

• One proton to one neutron

• One proton to two neutrons

• Equal number of protons and electrons

What is the hyphen form of isotopic notation?

• Element symbol followed by mass number

• Mass number followed by element symbol

• Element name followed by mass number

• Element name followed by atomic number

In nuclear notation, where is the mass number placed in relation to the element symbol?

• As a superscript after the symbol

• As a subscript before the symbol

• As a subscript after the symbol

• As a superscript before the symbol

What does the average atomic mass of an element represent?

• The mass of the least common isotope

• A weighted average of all isotopes

• The total mass of all isotopes combined

• The mass of the most common isotope

How can you determine the number of neutrons in an isotope if you know its mass number and atomic number?

• Divide the mass number by the atomic number

• Add the atomic number to the mass number

• Multiply the atomic number by the mass number

• Subtract the atomic number from the mass number