chemistry - ions Flashcards
(39 cards)
What is independent variable?
The variable for which values are changed.
What does the limitation of the simple particle model include?
In the model there are no forces so all particles are shown as spheres and the spheres are solid.
What is the dependent variable?
The variable for which the value is measured.
What are control variable?
The ones which must be kept the same (constant).
What are the three states of matter?
Solid, Liquid and Gas.
The stronger the forces between the particles…
…the higher the melting and boiling point of the substance.
What are the three states of matter shown as in chemical equations?
(s) (l) (g) with (aq) for aqueous solutions.
Why do metal atoms lose electrons?
To become positively charged ions.
Why do non-metal atoms gain electrons?
To become negatively charged ions.
What is an ionic compound?
A giant structure of ions.
How are ionic compounds held together?
By strong electrostatic forces of attraction between oppositely charges ions.
What happens when atoms share pairs of electrons?
They form covalent bonds. These bonds between atoms are strong.
What have very large molecules?
Some covalently bonded substances such as polymers.
What have giant covalent structures?
Some covalently bonded substances such as chemical and silicon dioxide.
What represents a single bond?
A single line.
What do metals consist of?
Giant structure of atoms arranged in a regular pattern.
What are the electrons in the outer shell of metal atoms?
Delocalised so they are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds.
What is the melting and boiling point of ionic compounds? And Why?
High because of the large amounts of energy needed to break the many strong bonds.
What happens when ionic compounds are melted or dissolved in water?
They conduct electricity because the ions delocalised and so charge can flow.
What substance consist of small molecules?
Usually gases or liquids that have relatively low melting and boiling points.
What happens with the intermolecular forces between small molecules?
They increase with the size of the molecules so larger molecules have higher melting and boiling points.
How are the atoms in the polymer molecules linked?
To other atoms by strong covalent bonds.
How strong are the intermolecular forces between polymer molecules?
Relatively strong so these substances are solids at room temperature.
What substances consists of giant covalent structures?
Solids with very high melting points which its atoms are all linked by strong covalent bonds.
