Additional Chemistry Flashcards
What are the masses and charges of these parts of an atom?
- Proton
- Neutron
- Electron
Protons = +ve
(mass 1)
Neutrons = neutral
(mass 1)
Electrons = -ve
(mass approx 0)
Why do atoms usually have no overall electrical charge?
Atoms usually have no overall charge because they have equal numbers of protons (+ve) and electrons (-ve), which cancel one another out
All atoms of a particular element (e.g. carbon) all have the same number of what?
Protons
The number of Protons in the nucleus of an atom is called the
Atomic number
The number of Protons + Neutrons in the nucleus of an atom is called the
Atomic mass
What is an alloy and why are they used?
Give some examples
Alloys are mixtures of metals with other elements, e.g. iron + carbon → steel
They have a combination of properties, e.g. bronze, brass, steel etc…
What is a smart alloy and why are they used (shape-memory)?
Give some examples
Smart alloys can return to their original shape after being deformed – e.g. glasses and braces
What do these terms means: -
- Element
- Compound
- Mixture
Element – pure substance with only 1 type of atom (e.g. gold)
Compound – 2 or more elements chemically bound (e.g. carbon dioxide)
Mixture – more than 1 element or compound not chemically bound (e.g
What are the symbols for the following atoms: -
Oxygen Nitrogen Chlorine Hydrogen Sodium Copper Potassium Helium Calcium Zinc Iron Carbon
Oxygen (O) Nitrogen (N) Chlorine (Cl) Hydrogen (H) Sodium (Na) Copper (Cu) Potassium (K) Helium (He) Calcium (Ca) Zinc (Zn) Iron (Fe) Carbon (C)
What happens to atoms when they chemically react to form a compound?
They share, give away, or take electrons
What are the names of these compounds, and which atoms are found in them?
H2O CaCO3 H2SO4 HCl CO2
Water (H2O)
Calcium carbonate (CaCO3)
Sulfuric acid (H2SO4)
Hydrochloric acid (HCl)
Carbon dioxide (CO2)
What is an isotope?
An isotope is an atom with a different amount of neutrons
How can you tell which group an atom is in, just by looking at it’s outer shell structure?
The number of electrons in the outer shell is the same as their group number
How many electrons can occupy the 1st and 2nd shell (energy level) of an atom?
2 in the 1st shell and 8 in the 2nd shell
The electron structure of sodium can be represented as 2,8,1 – what does this mean?
Represent these atoms: - • Fluorine • Oxygen • Potassium • Magnesium
2,8,1 means 2 electrons in the 1st shell, 8 electrons in the 2nd shell and 1 electron in the 3rd shell
Fluorine = 2,7
Oxygen = 2,6
Potassium = 2,8,8,1
Magnesium = 2,8,2
Define these terms: -
- Element
- Compound
- Mixture
Element – a pure substance made from 1 type of atom only
Compound – 2 or more elements chemically bound
Mixture – 2 or more elements or compounds mixed together which are not chemically bound
What happens to the electrons of 2 atoms when they chemically react?
During a chemical reaction electrons are either given away, taken, or shared
What is an ion?
How are +ve ions formed?
How are -ve ions formed?
An ion is an atom with a charge
+ve ions have lost electrons
-ve ions have gained electrons
Explain how the following atoms become ions (will they be +ve or –ve)?
- Potassium
- Magnesium
- Chlorine
- Oxygen
Potassium – loses 1 electron (K+)
Magnesium – loses 2 electrons (Mg2+)
Chlorine – gains 1 electron (Cl-)
Oxygen – gains 2 electrons (O2-)
What are the melting and boiling points of ionic compounds like?
Why is this?
Ionic compounds have high melting points and boiling points – to melt them you have to supply enough energy to break the 6 bonds attached to each ion
What happens to the electrons when atoms form ionic bonds and covalent bonds?
Which is the strongest?
Ionic bonds – 1 atom loses electrons and another gains electrons
Covalent bonds – electrons are shared
An individual covalent bond is stronger than an ionic bond
What are the melting and boiling points of covalent compounds like?
Explain why this is
Covalent compounds have low melting and boiling points (are often gases) are there is no attraction between the molecules
How are the elements of the periodic table arranged?
What are the rows called?
What are the columns called?
Elements are arranged in order of atomic number
Rows are called periods
Columns are called groups
Which 2 elements would be out of order in the periodic table if they were arranged by atomic mass instead of atomic number?
Potassium and Argon