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
Name the three categories into which elements are classified into based on their general properties.
Metals
Nonmetals
Metalloids
Do all metals react to oxygen in the same way?
No
Across a period from left to right, the element becomes (more, less) metallic and (more, less) nonmetallic in their properties.
Less,
More
Elements within a group have the (same, different) number of valence electrons.
Same
The reactivity of alkali metals (increases, decreases) from the top of Group 1A to the bottom.
Increases
Why is sodium stored under oil?
Because it reacts with water vapor in the air
Differences in reactivity amount on the alkaline earth metals are shown by the way they react with what?
Water
What does magnesium help/used for?
Helps plants produce sugar,
Is used to make lightweight bicycle frames
What does calcium help/used for?
Helps build strong teeth,
Is the main ingredient in limestone
Is aluminum more reactive than sodium and magnesium?
No
What is the most abundant metal in Earth’s crust?
Aluminum
Aluminum is often found combined with oxygen and what?
Bauxite
Except for water, what compound is most contained in your body?
Carbon
What is the most abundant element in Earth’s crust?
Oxygen
Halogens have similar ________ properties but different __________ properties.
Chemical,
Physical
What are three characteristics of the noble gasses?
Colorless,
Odorless,
Extremely unreactive
How can an element that does not react easily with other elements be useful?
It can be used to prevent reactions with highly reactive elements
Define the following:
An arrangement of elements in columns based on a set of properties that repeat from row to row
Periodic table
Define the following:
A pattern of repeating properties that occurs when atomic numbers are used to arrange elements into groups
Periodic law
Define the following:
One-twelfth the mass of a carbon-12 atom
Atomic mass unit
Define the following:
Elements that are good conductors of heat and electric current
Metals
Define the following:
Elements that form a bridge between the elements on the left and right sides of the periodic table
Transition metals
Define the following:
Elements that are poor conductors of heat and electric current
Nonmetals
Define the following:
Elements with properties that fall between those of metals and nonmetals
Metalloids
Define the following:
An electron that is in the highest occupied energy level of an atom
Valence electron
