Ch. 5 Flashcards
What were elements organization based on?
On their properties
The first elements to be identified were mainly what?
Metals
What was Mendeleev’s strategy for classifying elements modeled on?
Card game
What did Mendeleev know about each element?
The name, relative mass, and properties
How did Mendeleev arrange the elements into rows?
By their increasing masses
A periodic table is an arrangement of ________ in columns, based on a set of properties that repeat from row to row.
Elements
Why did Mendeleev leave some locations on his periodic table blank?
He left them for elements that had not been discovered
Was Mendeleev the first person to arrange the elements in a periodic table?
No
How can you tell if a scientific model is correct?
By wether it can be used to make accurate predictions
What did Mendeleev use to locate undiscovered elements?
Properties of elements
What did the close match between Mendeleev’s predictions and the actual properties of new elements show?
The usefulness of his periodic table
How are elements arranged in the modern periodic table?
By the increasing number of protons
Why does the number of elements per period vary?
The number of available orbitals increases from energy level to energy level
What value depends on the distribution of an elements isotopes in nature?
Atomic mass
Most elements exist as what?
A mixture with two or more isotopes
Is the mass of chlorine-37 greater or smaller than the mass of the atom chlorine-35?
greater