Atomic Structure

Question 1

What is the equation to illustrate the relationship between the angle of deflection and the charge-to-mass ratio of particles in the beam?

Answer 1

Angle of deflection=k(charge/mass)

Question 2

Define mass number/nucleon number

Answer 2

Mass number is defined as the total number of protons and neutrons in the nucleus of an atom

Question 3

Define atomic number/proton number

Answer 3

Atomic number is defined as the number of protons in the nucleus of an atom.
*The atomic number is. a fundamental characteristic of an element, each element has a unique atomic number.

Question 4

Define isotopes

Answer 4

Isotopes are atoms of the same element with the same number of protons but different number of neutrons. (number of electrons unchanged)=same chemical properties
different number of neutrons, different masses = different physical properties (density, m.p)

Question 5

Define isoelectronic species

Answer 5

Isoelectronic species refers to a group of atoms or ions having the same number of electrons. (F-, Ne, Na)

Question 6

What is meant by alpha emission/decay?

Answer 6

It involves the loss of a He particle. Nucleon number decreases by 4 and atomic number decreases by 2. (by the law of conservation of mass)

Question 7

What is meant by beta emission/decay?

Answer 7

It involves the loss of a beta particle (top 0, bottom -1).
By law of conservation of mass, check that
A(LHS)= B + C(RHS)

For both top and bottom values. *Total number of p, n and e remains the same after radioactive decay.

Question 8

What is an electronic structure of an atom?

Answer 8

Atom->PQS->Subshells->Orbitals->Electrons

Question 9

What is the relative energy of sub shells?

Answer 9

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Question 10

What is an atomic orbital?

Answer 10

An atomic orbital is defined as a region of space I which there is a 95% probability of locating the electron residing in it.

Question 11

What is the shape of s orbitals?

Answer 11

spherical in shape

Question 12

What is the shape of p orbitals?

Answer 12

dumb-bell in shape. Draw the three p orbitals

Question 13

What is the shape of d orbitals

Answer 13

For d orbitals except d(z)(2), the shape is a clover lead distribution. Draw the 5 d orbitals.

Question 14

State the order in which electrons are added to the orbitals.

Answer 14

1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 4s(2) 3d(6) 4s(2)

Question 15

What is the force experienced by electrons of parallel spins occupying doubly in orbitals of a subshell.

Answer 15

inter-electronic repulsions

Question 16

What are the two metals that have anomalous electron configurations? What kind of electronic configurations fo they have vs what they are expected to have?

Answer 16

Chromium and Copper.
Electronic configurations with full or half-filled 3d sub shell are unusually stable.
Cr(24): [AR]3d(5) 4s(10
Cu(29): [AR} 3d(10) 4s(1)

Question 17

What are the three factors that affect strength of electrostatic attraction between the nucleus and the electrons?

Answer 17

• Nuclear charge
• Shielding effect
• Number of PQS

Question 18

What is effective nuclear charge?

Answer 18

It is the resultant positive charge experienced by the valence electrons, taking into consideration the shielding effect of the inner electrons.
Effective nuclear charge=Nuclear charge-Shielding Effec t