Yes, it is correct, they have the 2 outermost shells incomplete and valence electrons are available from them. They are also called d block elements.The three long periods 4^th ,5^th,6_th periods come in this.

Yes, it is correct. Cathode rays was discovered and properties were established by him.

It is correct as it is a natural indicator extracted from lichens. It has purple colour in distilled water.

Yes , it is correct as all the three options affect the Ionization energy.of an element.

It is correct as for neutral solution  the pH is =7.

Yes, it is correct as along the period electrons are added in the same outer shell.

It is correct. According to Arrhenius, acids when mixed with water produces hydrogen ions.

It is correct as sulphur dioxide has a pungent smell.

It is correct, he observed when elements with similar chemical properties were grouped together with increasing atomic masses, occured in groups of three.These are called Triads.

It is correct because Mendeleev was able to predict the existence and even properties of some elements and so he left space for them in the periodic table.

Yes, it is correct. It starts with element Francium. This period contains the heaviest element which occurs naturally on earth, uranium. Most of the subsequent elements in this period have been synthesized artificially and on many  elements of this period work is still going on in the lab.  All elements are radioactive in this period.

It is correct as this statement is incorrect. Both the quantities will be equal.

It is correct as momentum = mass *velocity therefore unit is kg*m/sec, impulse =force*time. Therefore unit = (kg*m/sec*sec)*sec=kg*m/sec.

Yes, it is correct as it was at rest initially before it started , its speed will be zero at that time , then it acquires a certain speed and finally when it stops its speed will be zero again.

Yes, it is correct as it has only magnitude. So it is a scalar quantity.

It is the maximum in diamond i.e. 12000m/sec.

It is correct as by the time water has cooled to 4⁰C., the molecules' energy has dropped enough that they are very near each another. So each H₂O molecule forms more stable hydrogen bonds, with up to four fellow molecules. At 0⁰C, the molecules in ice are held rigidly apart. That means more empty space between molecules, so frozen water occupies more room and is less dense.

Yes, all are correct as work done is a product of force exerted on the body and the distance moved by the body in the direction of the force. Its unit is kg*m*m/sec*sec. Kinetic energy is energy associated with motion of a body and is measured in kg*m*m/sec*sec. Potential energy is the energy stored in the body due to its position and is measured in kg*m*m/sec*sec.

Yes, it is correct as it is beyond the audibilty range for us ie 20Hz - 20,000 Hz.

It is correct this is also known as terminus, it is where glacier first starts melting.

It is correct. In 1724, Daniel Fahrenheit made a temperature scale using mercury for the first time.

It is correct as when the pendulum reaches the very bottom of the swing, it is at its lowest point and greatest speed. This means that the pendulum has zero potential energy and maximum kinetic energy.

It is correct as water molecules are less dense than ice. Water expands on cooling.

Yes, it is correct as no new shell is added and electrons are added in same shell which increases ionization energy . An increase in ionization energy means decrease in size.

Yes, it is correct as the train is moving forward with acceleration and acceleration is the change in velocity of body with time, i.e. direction is also considered. Here the ball goes up and by that time the train moves forward , resulting in ball falling behind the child.