Chapter 3 elements and compounds Flashcards
What is the smallest piece of an element that is capable of independent existence?
An atom
Who wrote the atomic theory?
John Dalton, he described Adams as indivisible
The most abundant element on earth is what
Oxygen due to its presence in the atmosphere, as well as in rocks, sand and soil it’s also the most abundant element in the human body, followed by carbon and hydrogen
Sublimation means what
To change directly from a solid to a gas
Characteristics of noble gases
Found in nature in pure form, low reactivity
Most metal elements are what state at room temperature
Salad except mercury, which is liquid
What are properties shared by medals?
Shiny/high luster, ductile, malleable, good conductors, high melting points
What are alloys
Metals physically mix to make a special solution such as bronze brass
What are non-metal characteristics
Dial in appearance, low, melting, point poor conductor brittle
What are metalloids
Elements with properties midway between metals and nonmetals, sometimes called semi conductors, touching the stair step in the periodic table
What does the word periodic mean
Repeating, according to a pattern
Explain Dimitri mendeleev contributions
Successfully organized elements into official table, organized the elements in order of increasing atomic weight, so elements with similar properties with land in the same role
What’s the difference between vertical and horizontal columns in the periodic table?
Vertical columns are groups or families with similar properties, horizontal rows are. And do not have similar properties.
Characteristics of alkali metals
Extremely reactive metals found in the first column group one
Characteristics of alkali earth metals?
Reactive metals found in the second column, group 2
Where are transition elements found?
Groups three through 12
Characteristics of halogens
Very reactive nonmetals found in group 17
Characteristics of noble gases
Highly on reactive nonmetals found in the final group 18
To the left of the stair step, what are all elements except for one
Metals, except for hydrogen. The elements to the right of the stairstep are nonmetals elements that touch the stairstep are metalloids.
Are most elements free in nature
No elements are reactive, and have already combined with other elements usually
What is a diatomic molecule
A molecule that always contains two elements of the same element bonded together. These are hydrogen, nitrogen, oxygen fluorine chlorine, bromine iodine.
What are compounds?
A substance that’s composed of two or more elements, Chemically combined in a Definite ratio
What are the two types of compounds
Molecular and ionic
What is a molecular compound?
Made up of individual molecules, composed of atoms
What is an ionic compound?
It’s formed from ions that are either positive or negative
What are the representative elements?
Groups one, two, and 13 through 18
What’s the difference between a compound and a mixture?
Compound:
Combined chemically,
distinct substance
combined in a definite ratio
Mixture:
Combined, physically,
individual components retain their own properties,
variable in composition
What is a molecule
The smallest piece of a compound capable of independent existence
What is an ion?
Positive or negative charged atom or group of atoms
What is a positive charged ionic compound called?
Cation. Negative is called anion.
Technically the smallest piece of an ionic compound capable of independent existence is called what
Formula unit rather than a molecule
What is the subscript in a chemical chemical formula represent?
The number of atoms of each element present in a molecule or formula unit
What’s the difference between a molecule and an atom?
 A molecule is the smallest of a compound,
an atom is the smallest element capable of independent existence.
This is my note is it correct?
In a chemical formula, what happens when we have a parentheses?
The subscript on the outside is applied to all elements grouped by the parentheses
What is the law of definite composition?
A compound always contains two or more elements, chemically combined in a definite proportion by mass
What is mass
The amount of matter in an object, it’s like wait only weight equals the amount of gravity on an object which is dependent on location
What is the law of multiple proportions?
Atoms of two or more elements may combine in different ratios to produce more than one compound
