سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 6798)

(1) Great progress in science come not only when a scientist sees something new, but also when a scientist sees what everyone else has seen in a new way. In other words, great scientists see patterns where others have seen only disjointed facts. Such was the case in 1869 when Dmitri Mendeleev (1834-1907), a chemistry professor, saw a pattern in the properties of elements. Mendeleev’s insights led to the periodic law and the periodic table, arguably the single most important tool for a chemist. Mendeleev’s periodic law and periodic table summarize a large number of observations, and science moves forward by devising theories that explain the underlying reasons for these laws and observations. Quantum mechanics is the theory that explains the underlying reasons for the periodic table. (2) The modern periodic table is credited mainly to the Russian chemist Dmitri Mendeleev even though a similar organization had been suggested by the German chemist Julian Lothar Meyer (1830-1895). Mendeleev’s table is based on the periodic law, which says that when elements are arranged in order of increasing mass, their properties recur periodically. Mendeleev arranged the elements in a table in which mass increased from left to right and elements with similar properties fell in the same columns. (3) Mendeleev’s arrangement was a huge success, allowing him to predict the existence and properties of yet undiscovered elements such as eka-aluminium (later discovered and named gallium) and eka-silicon (later discovered and named germanium). What is one important idea about great scientists that the writer mentions in Paragraph (1)?