S3 - Chemistry Test (2) Flashcards
What is the formula mass and how is it obtained?
- The mass of all the atoms in a formula
- By adding the R.A.M of each atom
What is 1 mole equal to in chemistry?
1 gram formula mass
What does ‘a.m.u’ stand for?
Where do we most commonly put it?
- Atomic Mass Units
- After the formula mass
What charge do the following have:
- Neutrons
- Protons
- Electrons
- No charge
- Positive
- Negative
The atomic number of an atom is equal to the number of…
Protons and electrons
What is the centre of an atom called and what charge does it have?
- The nucleus
- Positive charge
Where are the following found in an atom:
- Neutron
- Proton
- Electron
Neutrons and Protons = Nucleus
Electron = Orbiting the nucleus
Atoms have the same number of…
Protons and electrons
What is the group number in the periodic table equal to?
The number of outer electrons
What is the mass of the following:
- Neutron
- Proton
- Electron
- 1
- 1
- 0
How do we work out the Mass numbers?
No. of protons + No. of neutrons
What do all elements need to be?
Stable
What group of the periodic table are stable?
The Noble Gases
What do elements need to have to be stable?
A full outer shell of electrons
What do elements need to do to create a full outer shell?
Share / steal electrons
What happens when 2 non-metal atoms share electrons?
A molecule is formed
What is a shared pair of electrons called?
A covalent bond
Covalent network substances are…
Solid at room temperature, usually very hard and have high boiling points
Do covalent network substances react?
No, they are unreactive
What are the covalent network substances?
Boron, Carbon (in the form of diamond and graphite) & silicon
What do non-metal atoms do to form a full outer shell of electrons?
Steal electrons form metals
What do metals do to achieve a full outer shell of electrons?
Give electrons away
How do we tell if a substance is ionic or covalent?
If the substance contains a metal it is ionic
What happens to ionic substances that doesn’t to covalent?
They dissolve in other substances
How do we work out the number of:
- Protons
- Electrons
- Neutrons
In an atom?
- Protons = Atomic No.
- Electrons = Atomic No.
- Neutrons = Mass No. — Atomic No.
What is an ion?
An atom with a different number of protons and electrons due to electrons being shared / stolen to form a full outer shell in an atom
What is an ionic bond?
The electrostatic force of attraction between a positively charged metal ion and a negatively charged non-metal ion
How do we tell if an element is positively or negatively charged?
If the atom gives away an electron to gain a full outer shell of electrons it is positively charged as it has less electrons than protons.
If an atom steals electrons it is negatively charged as it has more electrons than protons
What is a covalent bond?
A shared pair of electrons
Do covalent molecular and network substances conduct electricity?
No, this applies in any matter as well
Do ionic substances conduct electricity?
They are poor conductors as a solid but conduct well when molten or in solution.
Ionic substances have low melting points - True or False
False
What is the only type of compound with a low melting point?
Covalent molecule
The only type of compound to conduct as a solid is…
Metallic lattice
