Unit 3 Exam - Atomic Structure (Marsicano)

Who was the ancient Greek philosopher who first proposed the concept of indivisible particles called 'atomos'?

• Aristotle

• Plato

• Socrates

• Democritus

The smallest particle of an element that retains the properties of that element is a(n) ____.

• Atom
• Electron
• Proton
• Neutron

Which discovery did J. J. Thomson make that improved upon Dalton's atomic theory?

• Atoms contain tiny, negatively charged electrons
• Atoms are always in motion
• Atoms contain a tiny, positively charged nucleus
• Atoms that combine do so in simple whole-number ratios

An atom is considered neutral when:

• The number of protons is greater than the number of electrons

• The number of electrons is greater than the number of protons

• The number of protons is equal to the number of electrons

• The number of protons, electrons, and neutrons are all equal

The particles that are found in the nucleus of an atom are ____.

• Neutrons and electrons
• Electrons only
• Protons and neutrons
• Protons and electrons

The atomic nucleus consists of:

• Protons and electrons

• Protons and neutrons

• Electrons and neutrons

• Protons, neutrons, and electrons

An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.

• 152 protons and 76 electrons
• 76 protons and 0 electrons
• 38 protons and 38 electrons
• 76 protons and 76 electrons

The sum of the protons and neutrons in an atom equals the ____.

• Atomic number
• Mass number
• Nucleus number
• Atomic mass

What does the number 84 in the name krypton-84 represent?

• The atomic number
• The mass number
• The sum of the protons and electrons
• Twice the number of protons

All atoms of the same element have the same ____

• Number of neutrons
• Number of protons
• Mass numbers
• Mass