Chapter 1:Atoms, molecules and ions

1 Which of the following number of subatomic particles of carbon atom is correct?

• 6 protons and 6 neutrons

• 12 protons and 6 neutrons

• 6 protons and 12 neutrons

• 12 protons and 12 neutrons

Tags

NGSS.MS-PS1-1

Which of the following information are obtained directly from a mass spectrum?

I Number of isotopes present

II Molar mass of the isotopes

III Molecular formula of a compound

IV Percentage abundances of isotopes

• I and II

• II and III

• III and IV

• I and V

In an experiment, a compound was found to contain 15% of hydrogen and 85% of carbon by mass. What is the empirical formula of this compound?

• CH₂

• CH₄

• C₂H₄

• C₄H₁₀

What is the mass of 3.35 moles of sulfur trioxide

• 335 g

• 268 g

• 245 g

• 125 g

A subatomic particle that has a negative charge is called a(n)

• proton

• neutron

• electron

• nucleus

An iron atom has an atomic mass of 56. Its atomic number is 26. How many neutrons does the iron atom have?

• 30

• 26

• 56

• 82

An atom’s mass number equals the number of

• protons plus the number of electrons.

• proton plus the number of neutron

• protons

• electrons

A sample of element X contains 90% X-35 atoms,

8.0% X-37 atoms, and 2.0% X-38 atoms. The

average atomic mass will be closest to which

value?

• 35

• 37

• 36

• 38

The atomic mass of an element is defined as the weighted average mass of that element’s

• naturally occurring isotopes

• least abundant isotope

• radioactive isotopes

• most abundant isotope

What is the total number of electrons in an Mg²⁺ ion?

• 2

• 10

• 12

• 24