Question

multiple-choice question only after the discovery of ______ in the 1890s, could scientists begin to understand the true nature of chemical bonds. oxygen protons neutrons electrons rewatch

Explanation:

To determine the correct answer, we analyze each option:

• Oxygen was discovered much earlier (1770s), so it's not relevant here.
• Protons were discovered in 1919, later than the 1890s.
• Neutrons were discovered in 1932, also later than the 1890s.
• Electrons were discovered in the 1890s (by J.J. Thomson), and understanding electrons was crucial for understanding chemical bonds (as chemical bonds involve electron interactions).

Answer:

electrons (the option corresponding to electrons, assuming the last option is electrons with a typo as "electrong" which should be "electrons")