Acids And Bases Flashcards
The amount of basic atoms are:
118
Lustrous
They shine when polished
Malleable
They can be bent into new shapes without breaking
Ductile
Can be stretched into wires
Element cannot
Be broken down into more fundamental substances
There are ____ known elements arranged in order of their atomic number
118
___ atoms are made in the
20, laboratory
—- types of atoms are found naturally on earth
98
Crystal lattices
Are grid like structures (sio2)
Element is a substance whose atoms all
have the same number of protons: element’s atoms have the same atomic number
Compound
A substance that results from a combination of two or more different chemical events. They are held together by chemical bonds that are difficult to break
Mixture
Composed of two or more seperate elements
Inside atoms
Atoms are made up of even smaller particles known as subatomic particles
Electrostatic attraction
Negative charge of electrons causes them to be attracted to the positively charged protons
Repulsion
Opposite charges (+/-) attract each other like charges (+/+) (-/-) repel each other
Electron cloud
Used to describe where electrons are when they go around the nucleus of an atom
Neutron
It is a subatomic particle (smaller than or occurring within an atom). Neutrons have zero change = are neutral particles (not supporting // no strong features)
Proton
Electrically charged. Relative charged of +1. The number of protons is an atom is called its atomic number
Nucleus
Is a small, dense region consisting of protons and neutrons at the centre of an atom
Atomic number and mass number
Number if protons in the nucleus determines the type of atom it is and what element it belongs to. All atoms of a particular elect have the same atomic number (number of protons). E.g. gold atoms contain 79 protons. Number of neutrons affect the atom’s mass. Number if protons + neutrons = mass number. And mass number - atomic number = number of neutrons
Electrons and the nucleus
The number of electrons surrounding the nucleus of an atom is exactly equal to the number of protons in the nucleus. Atoms have no electric charge (charge neutral)
Alloy
Is known as a base metal. Combined with small amounts of other elements. (Defined by a metal bonding character)
Metals are
Dense
Electrical conductors
Malleable
Most metals are solid at room temperature
Ductile (stretch and drawn into thin wires)
Lustrous (shine when polished/freshly cut)
Are thermal conductors (pass heat easily along/through)
Ions
Atoms can lose/gain electrons to become electrically charged particles called ions (formed as a cation). Ions has non-zero net electrical charge cation - positively/anion - negatively changed
Metalloids
Any chemical element which has properties between. Those of metals and non-metals or a mixture. Metalloids are semi conductors (conduct electricity under certain conditions)
Non-metals
Most non-metals are found naturally as gases in the air. (Sulfur in volcanoes) a few solids round in the earths crudh
Carbon
Pure carbon exists in several different forms called; allotropes
Amorphous carbon
Diamond
Graphite
Acid
An acid is a substance that releases hydrogen ions (H+) in an aqueous solution ( in gaining water)
Properties of acids are:
Corrosive Sour taste Turn blue litmus paper red React with some metals, releasing hydrogen gas and leaving salt behind Contact electicity Neutralised by bases
Bases and alkalis
Releases hydroxide ion (Oh-) (eg (naOH)s) Are caustic (ability to burn) Have a soapy, slimy feel Turn red litmus paper blue Butter taste Conduct electricity Neutralise acids
Use a weak base for things such as;
Soap and toothpaste
- when a base can be dissolved in water, it is known as alkali
- the solution it forms is called alkaline solution
- all bases have similar chemical properties
The strength of an acid depends on
How many hydrogen ions are released. (An acid is weak if only a few of its molecules release hydrogen ions)
A base is a substance that release hydroxide ions
(oH-)
Neutral on a pH scale is
7
7 (neutral) on a pH scale is
Distilled water
Measuring pH
Indicators are chemical that’s change colour to show whether a substance is acidic, neutral or basic. A common indicator is litmus paper.
Another way of measuring pH is to use
A pH meter
Allotropes
Different forms of the same element
Anion
An ion that has more electrons than protons and is negatively charged
Atomic number
The number of protons in the nucleus; the atomic number determines what type of atom it is
Base
A substance that releases hydroxide ions
Cation
An ion that has fewer electrons than protons and is positively charged
Mass number
The number of protons and neutrons in an atom
