Atomic Structure
Which statement correctly describes a molecule?
What is the relative charge of a neutron?
An atom of phosphorus has an atomic number of 15 and a mass number of 31. Calculate the number of neutrons in this atom.
Explain why atoms are electrically neutral. Which of the following provides the correct explanation?
Which row correctly states the relative mass and relative charge of an electron?
Which definition of isotopes would receive full marks in an examination?
Carbon-12 (¹²₆C) and carbon-14 (¹⁴₆C) are isotopes. How many neutrons does carbon-14 contain?
Isotopes of the same element have identical chemical properties. Which statement correctly explains why?
Magnesium has three isotopes: ²⁴Mg with 79% abundance, ²⁵Mg with 10% abundance, and ²⁶Mg with 11% abundance. Calculate the relative atomic mass of magnesium.
A student calculates the relative atomic mass of chlorine by finding (35 + 37) ÷ 2 = 36. The accepted value is 35.5. Which statement explains the student’s error?
Silicon has three isotopes: ²⁸Si (92.2% abundance), ²⁹Si (4.7% abundance), and ³⁰Si (3.1% abundance). Calculate the relative atomic mass of silicon to one decimal place.
A particular atom has 19 protons, 20 neutrons, and 19 electrons. Which statement about this atom is correct?
A researcher discovers a new sample of an element containing two isotopes. Isotope X has a mass number of 50 and 40% abundance. Isotope Y has a mass number of 52 and 60% abundance. The relative atomic mass of this element is closest to which value?
An element Z has a relative atomic mass of 10.8. It has two isotopes: one with mass number 10 and one with mass number 11. Determine the percentage abundance of the isotope with mass number 11.
A forensic scientist analyses a bone fragment and determines it contains carbon-14 atoms. A student claims that carbon-14 atoms react differently from carbon-12 atoms in combustion reactions. Which response correctly evaluates this claim?
The notation ²³₁₁Na represents a sodium atom. Which combination correctly states the number of each sub-atomic particle in this atom?
Which statement about the nucleus of an atom is correct?
A sealed container holds pure oxygen gas. A student states: “The container contains oxygen atoms.” Suggest why this statement is not fully correct, and identify the more accurate term.