Lecture One -states Of Matter ,elements Flashcards
What are the three states of matter?
Solid, liquid, gas
States of matter depend on the arrangement of particles.
Define ‘matter’.
Anything that has mass and occupies space
Matter can be classified by physical state or composition.
What is an element?
A substance made up of atoms with the same atomic number
Elements cannot be broken down by chemical means.
What is a compound?
Two or more different elements bonded together
Compounds have a constant composition.
What is the smallest unit of an element?
Atom
Atoms are represented by atomic symbols.
What is the formula for Sodium Chloride?
NaCl
Sodium Chloride is formed from sodium and chlorine.
What are the components of an atom?
Nucleus (protons + neutrons) and electrons
Electrons surround the nucleus.
What is an isotope?
Atoms with the same number of protons but different numbers of neutrons
Isotopes can affect the properties of an element.
Fill in the blank: A _______ consists of two or more atoms held together by chemical bonds.
Molecule
Molecules can be made of the same or different elements.
What is the difference between a molecule and a compound?
All compounds are molecules, but not all molecules are compounds
Molecules can consist of the same elements, while compounds cannot.
What is the atomic number?
Number of protons in an atom
It is also equal to the number of electrons in a neutral atom.
What is the mass number?
Number of protons + number of neutrons
It reflects the total number of particles in the nucleus.
True or False: All elements can be broken down into simpler substances.
False
Elements cannot be broken down by chemical means.
What is the role of electrons in chemical bonding?
Electrons take part in the bonding of atoms
Valence electrons are particularly important.
What is a chemical formula?
Represents the number and types of atoms in a molecule
Example: H2O for water.
List three types of chemistry.
- Inorganic
- Organic
- Physical
Each type focuses on different aspects of chemical reactions and properties.
What happens to compounds when they dissolve in water?
They become electrically charged and are called ions
Example: NaCl dissociates into Na+ and Cl-.
What are common chemical formulas for water and carbon dioxide?
- Water: H2O
- Carbon dioxide: CO2
These formulas indicate the number of atoms of each element.
Fill in the blank: The _______ of a compound indicates how many atoms of each element it contains.
Chemical formula
This helps in understanding the composition of compounds.
What is VSEPR theory used for?
To predict the shape of molecules
VSEPR stands for Valence Shell Electron Pair Repulsion.
What is chemical kinetics?
The study of the rates of chemical reactions
It helps in understanding how different conditions affect reaction speed.
What is chemical equilibrium?
The state where the rates of the forward and reverse reactions are equal
At this point, the concentrations of reactants and products remain constant.
