Died: April 4, 1919, London, United Kingdom
British scientist and physicist Sir William Crookes OM PRS studied at the Royal College of Chemistry, which is now a division of Imperial College London, and focused on spectroscopy. He was a pioneer in the field of vacuum tubes, creating the Crookes tube in 1875.

Died: February 2, 1907, Saint Petersburg, Russia
Chemist and inventor Dmitri Ivanovich Mendeleev was from Russia. The Periodic Law and a modified version of the periodic chart of elements were two of his most famous creations.

Brightwater, Colony of New Zealand

Died：19 October 1937 (aged 66)

Cambridge, England

Ernest Rutherford, 1st Baron Rutherford of Nelson. (30 August 1871 – 19 October 1937) he was a New Zealand physicist who came to be known as the father of nuclear physics.

He found that the atom is mostly empty space, with nearly all of its mass concentrated in a tiny central nucleus. The nucleus is positively charged and surrounded at a great distance by the negatively charged electrons.

And then Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.

Died ：December 19, 1953 (aged 85)

San Marino, California, U.S.

He was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric effect.

The purpose of this experiment is to measure the electrical charge of a single electron. The method focuses on balancing gravity and electricity so that the oil droplet is suspended between two metal electrodes. The total charge of the whole oil droplet is also calculated from the known electric field strength.

Died: 10 August 1915 (aged 27)

He was an English scientist whose contribution to physics was the physical laws' justification of the atomic number's earlier empirical and chemical concepts. This came about as a result of his creation of Moseley's law in X-ray spectra.

Prior to Mosley's work, "atomic number" was simply the position of an element in the periodic table and was not known to be associated with any measurable physical quantity.

Copenhagen, Denmark

Died: 18 November 1962 (aged 77)

Copenhagen, Denmark

He was a Danish physicist who contributed significantly to the understanding of atomic structure and quantum theory. He was awarded the Nobel Prize in Physics in 1922 for his work in these fields. Bohr was a philosopher and an advocate for scientific investigation.

Died：24 July 1974 (aged 82)

Cambridge, England

He was an English physicist who, after discovering the neutron in 1932, received the 1935 Nobel Prize in Physics. He completed the MAUD Report's final draft in 1941, which prompted the American government to launch significant atomic bomb research initiatives. During World War II, he served as the leader of the British team that worked on the Manhattan Project. In 1945, he received a knighthood in Britain for his contributions to physics.