Answer:
ELEMENTS
COMPOUNDS
Elements are made up of one kind of atoms.
Compounds are made up of two or more kinds of atoms.
Elements cannot be broken down into simpler substances by any physical or chemical method.
Compounds can be broken down into simpler substances by chemical methods.
Elements have their own set of properties.
Properties of a compound differ from those of their elements.
Examples: Hydrogen, Oxygen
Examples: Water, Sodium chloride
Answer: a) 
: Decomposition
b) 
: double displacement
c) 
: Synthesis (Combination)
d) 
: redox
Explanation:
Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.
A double displacement reaction is one in which exchange of ions take place.
Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.
Redox reaction is a type of chemical reaction in which oxidation and reduction takes place in one single reaction. The oxidation number of one element increases and the oxidation number of other element decreases.
Answer:
B
Explanation:
Behaviour therapy was popularized by the U.S. psychologist B.F. Skinner, who worked with mental patients in a Massachusetts state hospital.
I think it will be D or B but my mine answer is D
The mass of electrons, protons, and neutrons:
electrons 9.10938291*10^-31 kg
protons 1.67262178*10^-27 kg
neutrons 1.6749*10^-27 kg
the mass of electrons is way smaller than both, the mass of protons and neutrons
therefore, 1) the mass of 2 electrons is the smallest
