Corticosteroids and prostaglandins can also decrease expression of class II MHC molecules.

TLS Online TPP Program

#Id: 7741

#Section 2: General Biology

Atomic radii: The atomic radii of an atom depends on its position in the periodic table.

We can never determine the atomic radius of an atom because there is never a zero probability of finding an electron, and thus never a distinct boundary to the atom.

All that we can measure is the distance between two nuclei (internuclear distance).

TLS Online TPP Program

#Id: 7739

#Section 2: General Biology

Atoms are characterised by:

Radius

Ionization energy

Electron affinity

Electronegativity

Metallic character

Oxidation potential

TLS Online TPP Program

#Id: 7738

#Section 2: General Biology

Which of the following are true for an element?

(i) Atomic number = number of protons + number of electrons

(ii) Mass number = number of protons + number of neutrons

(iii) Atomic number = number of protons = number of neutrons

(iv) Atomic number = number of protons = number of electrons

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (ii) and (iv)

TLS Online TPP Program

#Id: 7737

#Section 2: General Biology

Calculate the number of electrons, protons and neutrons in 1 mole of 16^O^-2 ions.

TLS Online TPP Program

#Id: 7736

#Section 2: General Biology

The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).

TLS Online TPP Program

#Id: 7735

#Section 2: General Biology

The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.