C4 Flashcards
Who was J.J. Thompson? (2 points)
- In late 1890s
* Discovered the electron
Who was John Dalton? (2 points)
- Early 1800s proposed a theory of atoms
* Proposed that all atoms of the same element were the same
Who was Ernest Rutherford? (2 points)
- In 1911
* Discovered the atom had a dense centre - nucleus
Who was Niels Bohr? (2 points)
- In 1911
* Predicted that electrons occupy orbitals
What has led to the current theory of atomic structure? (1 point)
• The work of John Dalton, J.J. Thompson, Ernest Rutherford and Niels Bohr
Who were Geiger and Marsden? (2 points)
- Collected some unexpected results of atomic theory
* Led to the model of the atom being modified in order to explain them
What is the structure of an atom? (1 point)
• Atom has a central nucleus surrounded by shells of negatively charged electrons
What is the nucleus of an atom made up of? (1 point)
• Protons and neutrons
What is the charge of an atom? (2 points)
- The nucleus is positively charged
* Atom has no overall charge
Why does an atom have no overall charge? (2 points)
- Same number of (positive) protons and (negative) electrons
* Charges cancel each other out
What is the approximate radius of an atom? (1 point)
• 1^-10m
What is the approximate mass of an atom? (1 point)
• 10^-23g
What is the relative charge of a proton? (1 point)
• +1
What is the relative mass of a proton? (1 point)
• 1
What is the relative charge of a neutron? (1 point)
• 0
What is the relative mass of a neutron? (1 point)
• 1
What is the relative charge of an electron? (1 point)
• -1
What is the relative mass of an electron? (1 point)
• 0.0005 (zero)
What is an element? (2 points)
- Made of 1 type of atom
* Can’t be chemically broken down
How many naturally occuring elements are there? (1 point)
• Over 100
What is a compound? (1 point)
• A substance made of 2 or more elements that are chemically combined
How can you identify the elements in a compound? (1 point)
• From its formula using the periodic table
What does the compound Sodium Chloride (NaCl) contain? (2 points)
- The elements Sodium (Na)
* And Chlorine (Cl)
What does the compound Potassium Nitrate (KNO3) contain? (3 points)
- The elements Potassium (K)
- Nitrogen (N)
- Oxygen (O)
What is the Mass Number? (1 point)
• The total number of protons and neutrons in an atom
What is the Atomic Number? (1 point)
• The proton number
How are the elements in the periodic table arranged? (1 point)
• In increasing atomic number
What can you use the periodic table to do? (2 points)
- Find an element from its atomic number
* The atomic number of an element
What is the group number? (1 point)
• The same as the number of electrons in the outer shell of an element’s atom
What is the period number? (1 point)
• The same as the number of occupied shells (shells that contain electrons) that an element’s atom has
What is an isotope? (1 point)
• Atoms of the same element that have the same atomic number but different mass number
What does each isotope have? (1 point)
• The same number of protons and electrons, but different number of neutrons
What is electron configuration? (1 point)
• Tells you how the electrons are arranged around the nucleus in shells (energy levels)
How many electrons can the first shell of an atom hold? (1 point)
• Maximum of 2
How many electrons can the shells other than the inside shell hold? (1 point)
• Maximum of 8
What is an ion? (1 point)
• A charged atom or group of atoms
What is a positive ion? (2 points)
- An atom or group of atoms that have lost one or more electrons
- E.G. Losing 2 electrons makes a 2+ ion
What is a negative ion? (2 points)
- An atom or group of atoms have gained 1 or more electrons
* E.G. gaining 2 electrons makes a 2- ion
What are the 3 things that happen in ionic bonding? (3 points)
- The metal atom loses all outer-shell electrons to become a positive ion
- The non-metal atom gains electrons to fill its outer shell (become a stable octet) to become a negative ion
- The positive and negative ions are attracted - called an ionic bond
What is ionic bonding? (2 points)
- Type of chemical bond that involves a metal and a nonmetal ion through electrostatic attraction
- In short, it is a bond formed by the attraction between two oppositely charged ions
What are 2 examples of ionically bonded compounds? (2 points)
- Sodium Chloride
* Magnesium Oxide
What are 4 properties of ionically bonded compounds? (4 points)
- High melting points
- Don’t conduct electricity when solid
- Dissolve in water
- Can conduct electricity when IN SOLUTION or when MOLTEN
What are 3 elements in the second period of the periodic table? (3 points)
- Lithium (Li)
- Carbon (C)
- Neon (Ne)
What does the period of an element relate to? (1 point)
• The number of occupied electron shells
If an element’s electronic structure is 2.8.6 (sulfur), what is it’s position in the periodic table? (2 points)
- 3 electron shells = third period
* 6 electrons in outer shell = group 6
What are the 3 types of bonding? (3 points)
- Ionic bonding = metals and non-metals
- Covalent bonding = non-metals
- Metallic bonding = metals only
What is covalent bonding? (1 point)
• Non-metals combine by sharing pairs of electrons
What are 2 examples of covalently bonded molecules? (2 points)
- Water
* Carbon dioxide
What does water (H2O) contain and what are its 3 properties? (4 points)
- Contains hydrogen and oxygen atoms
- Liquid at room temperature
- Low melting point
- Doesn’t conduct electricity
What does Carbon dioxide (CO2) contain and what are its 3 properties? (4 points)
- Contains carbon and oxygen atoms
- Gas at room temperature
- Low melting point
- Doesn’t conduct electricity
What is one molecule of water made up of? (1 point)
• 1 oxygen atom, 2 hydrogen atoms
What is one molecule of carbon dioxide made up of? (1 point)
• 1 carbon atom, 2 oxygen atoms
What are 2 examples of simple covalently bonded molecules? (2 points)
- Water
* Carbon dioxide
What do simple covalently bonded molecules have? (1 point)
• Weak intermolecular forces of attraction between molecules
Why do simple covalently bonded molecules have low melting points? (1 point)
• Because they have weak intermolecular forces of attraction between molecules
Why don’t simple covalently bonded molecules conduct electricity? (1 point)
• There aren’t any free electrons
Who was Dobereiner? (3 points)
- First to suggest Law of Triads, where he grouped the elements into sets of 3 with similar properties
- Middle element would have the average mass of other 2 elements
- But - not all elements were known, pattern did not work for every known element
Who was John Newlands? (2 points)
- First scientist to make a table of elements, called the Law of Octaves, where every 8th element behaved the same
- But - he included some compounds as he believed them to be elements
Who was Mendeleev? (4 points)
- The author of the modern periodic table
- He left gaps in his table for the unknown elements and made predictions about their properties
- His predictions were later proved correct
- Also, investigations on atomic structure agreed with his ideas
Where are the Alkali metals found in the periodic table? (1 point)
• Group 1