Topic 1 - Bonds Flashcards
What are isotopes?
Different atomic forms of the same element
What is an ionic bond?
A bond between a metal and a non-metal where the metal loses electrons and the non-metal gains so both have a full outer electron shell
What are the properties of an ionic compound?
Ionic compounds are strong and have high melting and boiling points. This is because of the strength of an ionic bond. They can also conduct electricity because of the presence of ions.
What is a simple covalent bond?
When non-metal atoms share electrons to get a full outer electron shell.
What are the properties of simple covalent compounds?
The covalent bond itself is very strong. But They have low melting and boiling points due to the very weak intermolecular bonds between molecules. They can’t conduct electricity due to the lack of ions.
What is a giant covalent structure?
When molecules are held together by strong covalent bonds instead of intermolecular bonds. Making them very strong.
Name some examples of giant covalent structures
Diamond
Nanotubes
Graphite
Buckministerfullerene
Why can’t diamond conduct electricity?
Because all of its electrons are locked in covalent bonds, so there are no free electrons to conduct the electricity
Why is diamond so strong?
Because the bonds between each molecule are made from covalent bonds with four pairs of electrons. These are extremely strong.
What format will you find an element displayed in the periodic table?
Mass Number (total relative mass) Symbol Atomic Number (protons/electrons)
Describe a metallic bond
There are rows of ions and a sea of delocalised electrons
What are the properties of a metallic bond?
They can conduct electricity due to the free flowing electrons. They are strong due to the strong attraction between ions, this also means they have a high melting and boiling point. They are malleable because the repeating rows of ions can easily slide over each other.
Explain how metallic bonds hold together
The electrostatic attraction between the positive ions and the negative electrons hold everything together
How did John Newlands arrange the elements?
In order of atomic mass
How did Mendeleev arrange his first periodic table?
In order of atomic mass
State two differences between Mendeleev’s periodic table and the periodic table today
The periodic table today is order based on atomic number, Mendeleev’s was ordered based on atomic mass.
Mendeleev’s table had gaps for undiscovered elements.
Why do simple covalent compounds have low boiling and melting points?
The only thing holding simple covalent molecules together are weak intermolecular bonds which only require a small amount of energy to be broken.
Describe the structure of ionic compounds
Each ion (apart from the ones on the outside) is surrounded by six ions of the other element. This repeats to create a giant lattice structure.
Why do ionic compounds have high melting and boiling points?
Each ion is bonded to six ions (the ones on the outside are bonded to four). There is a strong attraction between the negatively and positively charged ions, a lot of energy is required to overcome this attraction.
