Atomic Structure and History Quiz

Atomic Structure

• Atoms are mostly empty space
• Atoms contain a small, dense, positively charged nucleus
• The nucleus contains protons and neutrons
• Electrons orbit the nucleus
• Protons have a positive charge (+1)
• Neutrons have no charge (0)
• Electrons have a negative charge (-1)
• Location: Protons and neutrons are located in the nucleus, electrons are outside the nucleus

Atomic History

• Experiments like the cathode ray tube and gold foil experiments led to the understanding of atomic structure
• Alpha particles were deflected when passing near the positive nucleus
• The gold foil experiment showed that most of the atom is empty space

Atomic Numbers and Mass Numbers

• Atomic number = number of protons in an atom
• Mass number = number of protons + number of neutrons
• Isotopes have the same number of protons but different numbers of neutrons (different mass numbers)
• The average atomic weight on the periodic table is an average of the isotopes

Periodic Table Trends

• Atomic radius increases as you go down a group (due to more energy levels)
• Atomic radius decreases as you go across a period (due to increasing nuclear charge)
• Number of valence electrons increase as you move across a period, and repeat after each group-increase
• Number of energy levels increase going down a group
• Elements in a family have similar properties due to similar valence electrons
• Elements are categorized on the periodic table based on their electron configuration.

Isotopes

• Isotopes of an element have the same number of protons and electrons (same atomic number)
• Isotopes have different numbers of neutrons
• Isotopes have different mass numbers

Test your knowledge on atomic structure, including the roles of protons, neutrons, and electrons. Explore the historical experiments that led to our current understanding of atoms. Understand the concepts of atomic numbers, mass numbers, and isotopes.