Matter and Atomic Structure

which of the statements below is not true about molten lead?

• molten lead consists of lead atoms only

• lead atoms arranged in orderly manners

• the size of lead particles in molten state is the same as in solid state

• force of attraction between particles in molten lead is weaker compared to the force of attraction between particles in solid lead

water is made up of H2O molecules. which of the following reactions occurs when water is evaporated?

• arrangement of H2O molecules is more ordered

• distance between H2O molecules decreases

• H2O molecules become heavier

• energy content of H2O molecules increases

table beside shows the boiling and melting point of substances W, X, Y and Z. which of the following is a liquid at 100 degree celsius?

• W

• X

• Y

• Z

diagram beside shows the arrangement of particles in three states of matter at room temperature.

• x - chlorine, y- naphthalene, z - oxygen

• x - naphthalene, y - oxygen, z - chlorine

• x - oxygen, y - chlorine, z - naphthalene

• x - chlorine, y - oxygen, z - naphthalene

who discovered neutrons?

• neils bohr

• j.j thomson

• james chadwick

which of the following is not a statement of dalton's atomic theory?

• all matter consists of tiny particles known as atoms

• atoms cannot be divided into simpler particles

• atoms can be created or destroyed

• atoms of the same element are the same but atoms for different elements are different

the electron arrangement of atom X is 2.8.7 and it has 15 neutrons in its nucleus. what is the nucleon number of atom X?

• 31

• 32

• 33

• 34

diagram besides shows the standard presentation of nitrogen atom. what is the number of valence electrons of the atom?

• 5

• 8

• 9

• 10

diagram beside shows the heating curve of solid acetamide. which statement can be deduced from the diagram?

• no heat is absorbed at stage OP

• acetamide undergoes physical changes at stage PQ

• acetamide needs 8 minutes to melt completely

• the attractive forces between particles of acetamide become stronger after Q

which statement is true about isotopes of an isotope? an isotopes is an atom of a given element with

• same number of protons but different number of electrons

• same number of neutrons but different number of protons

• same number of protons but different number of neutrons

• same number of electrons but different number of neutrons