Answer:
a. atoms are the basic building blocks of matter. The atom is made of electrons and protons. It contains the chemical identity of an element.
b. Three types of particles that make up an atom are:
electrons - these are negatively charged particles and lightest constituents of an atom.
protons are positively charges and is 1873 times heavier than an electron.
Neutrons are neutral particles having mass equivalent to mass of proton.
Protons and neutrons exist in the center of an atom in nucleus and electrons revolve around the nucleus.
c. An atom is a neutral entity where as an ion is charged. An ion has excess of electrons or lacks electrons due to which it has negative or positive charge. An atom has an equal number of electrons and protons.
d. In a negative ion, the number electrons is greater than number of protons. The atom when gains electrons becomes negative ion.
e. John Dalton proposed Solid sphere model in which tiny invisible particles constitute matter. These invisible particles are atoms and these are indivisible.
Answer:
The temperature of the metal is 
Explanation:
From the question we are told that
The mass of the metal is 
The specific heat of the metal is 
The mass of the oil is 
The temperature of the oil is 
The specific heat of oil is 
The equilibrium temperature is 
According to the law of energy conservation
Heat lost by metal = heat gained by the oil
So
The quantity of heat lost by the metal is mathematically represented as

=> 
Where
the temperature of metal before immersion
The negative sign show heat lost
The quantity of gained t by the metal is mathematically represented as

=> 
So

substituting values

=> 
Answer:
The average force exerted on the window due to two snowballs is 6 N
Explanation:
Given:
Mass of snowballs
Kg
Velocity of snowball 
For finding the average force,
Force is equal to the change in momentum,

Here, final velocity is zero so we write,

Where
sec

N
Above value of force is due to one ball, but here given in question there are two ball,

N
Therefore, the average force exerted on the window due to two snowballs is 6 N
1
2 4. 5 4 5
+3 0 7. 3 0 0
——————
3 3 1 8 4 5
line up the decimal points and add.
hope this helps!