Chemists
This German chemist suggested that elements could be arranged in sets of three according to their property type.
Johannes Dobereiner
Sets of three elements that have similar properties
Triads
Dobereiner proposed that copper and silver have similar properties as this other element
Gold
What is the atomic number of helium?
2
This prefix from the Sanskrit word meaning "one" was used by Mendeleev to denote unknown elements
Eka-
This English chemist hypothesized that the chemistry of the elements might be related to their atomic masses.
John Newlands
Newland's law for classifying elements, which he theorized after noticing that elemental properties repeated every seventh element, as musical notes repeat every eighth note
Law of Octaves
Dobereiner proposed that chlorine and bromine have similar properties as this other element
Iodine
How many elements are on the modern periodic table?
118
The most commonly used model of the atom
The Bohr Model
Two scientists contributed to the formation of the modern table by focusing on relationships between atomic mass and various physical and chemical properties. Name the German one.
Julius Lothar Meyer
Moseley showed that the periodic arrangement of the elements was determined by this
Atomic Number
Newlands theory was not applicable for elements heavier than _____
Calcium
The year that Mendeleev published his first periodic table
1869
This law states that the chemical and physical properties of elements are a periodic function of their atomic number
Modern Periodic Law
Two scientists contributed to the formation of the modern table by focusing on relationships between atomic mass and various physical and chemical properties. Name the Russian one.
Dimitri Mendeleev
In Mendeleev's periodic table, the vertical columns are called _____
Groups
One demerit of Mendeleev's table was that no fixed position could be given to this element
Hydrogen
The year that Moseley discovered the underlying foundation of the order of the elements was by atomic number
1913
Moseley discovered that the arrangement of the elements was by atomic number, not atomic mass, while doing this
Analyzing the frequencies of x-rays emitted by the elements
This British physicist discovered that the underlying foundation of the order of the elements was by atomic number, not atomic mass.
H. G. J. Moseley
In Mendeleev's periodic table, the horizontal rows are called _____
Periods
Cobalt, whose atomic mass is 58.93, is placed before this element on the table, whose atomic mass is 58.71
Nickel
Mendeleev deliberately left blanks in his table at atomic masses of these numbers, in the expectation that elements with those atomic masses would be discovered (you only need to name one)
44, 68, 72, 100
The key difference between Mendeleev and Meyer's arrangements of the periodic table
Mendeleev did not assume that all the elements had been discovered