Chem 4 Flashcards
What is the structure of an atom
an extremely small, positively charged nucleus surrounded by a cloud of negatively charged electrons
How are elements ordered on the periodic table
in order of increasing atomic number.
What are the horizontal rows on the periodic table called
Periods
What are the vertical columns on the periodic table called
Groups
Why are te elements in the periodic table grouped in the way they are
Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.
Valency definition
Valency is the combining power of an element The valency of an element is related to how many electrons are in the outer shell.
Oxidation definition
A chemical reaction that takes place when a substance comes into contact with oxygen or another oxidizing substance. Examples of oxidation are rust and the brown color on a cut apple.
Reduction def
the gain of electrons, loss of oxygen, or gain of hydrogen
What is the reactivity series used for
to predict whether a metal can displace another in a single displacement reaction
The reactivity series was created by
using the observations of their reactions with oxygen, water and acid
What’s an exothermic reaction
a chemical reaction that releases energy by light or heat
What’s an endothermic reaction
chemical reactions in which the reactants absorb heat energy from the surroundings to form products
Group one elements are
soft, reactive metals with low melting points
Group two elements are
shiny, silvery-white in appearance, and possess relatively low densities
Group 3 on periodic table is
soft, silvery-white metals
Group 4 on periodic tables
hard, refractory metals
Group 5 on periodic table is
. Niobium has the largest known magnetic penetration depth of all the elements
G 7 on periodic table is
As you go down the halogens, from fluorine to astatine, the elements become darker in colour and have a higher boiling point
Common properties of metals are
malleable, ductile, good conductors of heat and electricity
Common properties of non metal are
bad conductors of heat and electricity (except graphite, may be solids, liquids or gases at room temperature
Polymers properties
tensile strength, durability, viscoelasticity, reactivity, melting point, conductivity
Uses of polymers
clothing made from synthetic fibers, polyethylene cups, fiberglass, nylon bearings, plastic bags,
Describe how carbon can be used to extract certain metals from their ores
by heating with carbon
How does the energy of particles Change as the change state
As heat energy is added, the particles gain more heat energy until they undergo the process of changing state, at which point their temperature remains constant.
F
Measure out 10 cm3 of hydrochloric acid and carefully add this to the sodium hydroxide solution in the polystyrene cup. Stir with the thermometer and record the maximum or minimum temperature reached. Work out the temperature change and decide if the reaction is exothermic or endothermic
