1. Atomic Structure Flashcards by Sehar Nadeem

3 Factors of the Bohr Model:

protons + neutrons are found in the centre of the atom called the nucleus
protons + neutrons can also be called nucleons
electrons orbit around the nucleus in shells/energy levels

How well did you know this?

Not at all

Perfectly

Name Fundamental Particles of an Atoms, their relatives masses and relative charges

How well did you know this?

Not at all

Perfectly

Atomic number is equal to the …

number of protons

How well did you know this?

Not at all

Perfectly

Mass Number is equal to …

the sum of the number of protons and neutrons

How well did you know this?

Not at all

Perfectly

Number of Neutrons =

Mass Number - Atomic Number

How well did you know this?

Not at all

Perfectly

What are isotopes?

Atoms with the same number of protons but different number of neutrons

How well did you know this?

Not at all

Perfectly

Why do isotopes of the same element have the same chemical properties?

They have the same electronic configuration

How well did you know this?

Not at all

Perfectly

Isotopes have the same electron configuration so …

They have the same chemical properties

How well did you know this?

Not at all

Perfectly

Why do atoms have a neutral charge?

Number of Protons = Number of Electrons

How well did you know this?

Not at all

Perfectly

What are cations?

An atom that has lost electrons so the number of protons are greater than the number of electrons. Positively charged ions.

How well did you know this?

Not at all

Perfectly

What are anions?

An atom that has gained electrons so the number of electrons are greater than the number of protons. Negatively charged ions.

How well did you know this?

Not at all

Perfectly

1st Ionisation Energy:

the amount of energy needed to remove a mole of e- from a mole of atoms, in the gaseous state. (units = kJ mol-1)

How well did you know this?

Not at all

Perfectly

Equation for the 1st ionisation energy (of Potassium, K):

K(g) → K+ (g) + e-

How well did you know this?

Not at all

Perfectly

1st 3 Ionisation Energies of Boron:

1: B(g) → B+ (g) + e-
2: B+(g) → B 2+ (g) + e-
3: B 2+(g) → B 3+ (g) + e-

How well did you know this?

Not at all

Perfectly

3 factors that influence I.E:

1) Shielding
2) Nuclear Charge (number of protons in the nucleus)
3) Distance from nucleus

How well did you know this?

Not at all

Perfectly

Trends in 1st I.Es of Elements Down A Group:

Shielding increases
(- Distance from nucleus increases)
Weaker attraction between nucleus and outermost e-
1st I.E decreases down group

How well did you know this?

Not at all

Perfectly

Why do I.Es 1 to 3 increase?

Each e- is being removed from a more +ve ion each time. (attraction between the electrons and the protons increase as there are less electrons being attracted by the same number of protons)

How well did you know this?

Not at all

Perfectly

Why does the 4th I.E increase drastically?

The 4th e- being removed from a shell closer to the nucleus and a more positive ion and so is much more strongly attracted to the nucleus

How well did you know this?

Not at all

Perfectly

Why is Li a bigger atoms than Be?

Study These Flashcards

Same shielding
Be has more protons
so, stronger attraction to the outer e-

Why is Li a bigger atoms than He?

Study These Flashcards

Li has an extra shell
Li’s outermost e- is further away from the nucleus
Outer e- is more shielded
Outer e- less strongly attracted to the nucleus

Which element has the highest 1st I.E of all the elements?

Study These Flashcards

He. Because it has the same shielding as H but has more protons than H.

Trend in 1st I.E across a period:

(use example of Period 3 to explain)

Study These Flashcards

General increase
Same shielding, grater number of protons, stronger attraction between nucleus and outermost e-
with 2 exceptions
Reasons for the exceptions
P subshell lower in energy than than the S subshell → less energy required to remove the e-
1st e- removed from P = 1p subshell + unpaired. 1st e- removed from S = 1p subshell + paired. P= lower I.E due to e- pair repulsion. Therefore, less energy needed to remove the e- from S.

Why does the atomic radius get smaller across the period?

Study These Flashcards

same shielding
number of protons increases
greater attraction between nucleus and electrons

What 2 factors does the mass spectrometer measure?

Study These Flashcards

1) relative abundance
2) mass/charge (m/z) ratio

Why is the inside of the mass spectrometer a vaccum?

to prevent any of the particles being tested from colliding with molecules from the air

Name the 2 ionisation methods:

1) electron impact 2) electrospray

Describe the accceleration step in mass spectrometry:

+ve ions attracted towards the -vely charged plate and accelerate towards it. amount of acceleration depends on the m/z ratio. High m/z ratio ions will accelerate slower than low m/z ratio ions. Once accelerated, all ions will have the same KE

Describe ion drift in mass spectrometry

Some ions pass through the hole in -vely charged plate, & travel along the flight tube towards detector. Travel at diff speeds = drift apart.

Describe detection in mass spectrometry

ions arrive at detector at diff time due to diff velocities. ‘Time of flight’ recorded as each ion hits detector and gains an e-, which generates a current, the size of which is proportional to the abundance of each type of ion

Describe data analysis in mass spectrometry

the signal from the detector is passed to a computer which generates an electric current

Why are sample particles ionised?

1) so they can accelerate towards the negatively charged plate 2) so they can generate a current when they hit the detector

How is the ion accelerated?

1) +ve ion attracted towards the -vely charged plate 2) all ions have the same KE

How are ions separated in the flight tube?

Low m/z ions travel at higher speeds + move ahead of those travelling more slowly (high m/z)

How are ions detected?

- each ion hits the detector - ion gains an e- - generate a current - size of current is proportional to the abundance of the ion

How do you find the mass from a m/z ratio?

M/Z value - 1

Describe electrospray ionisation as a method of ionisation:

- sample is dissolved in a volatile solvent - sample is injected through a hypodermic needle at a high voltage, producing a fine mist - sample is ionised by gaining a proton

Give an example equation for electrospray ionisation:

(H+ = proton) X + H+ → XH+

Describe electron impact as a method of ionisation:

- sample is vapourised - high energy e- are fired at sample - from an e- gun - 1 e- knocked off each particle

Give an example equation for electron impact:

X(g) → X+ (g) + e-

Ar Equation:

KE Equation

KE = 1/2 mv^2

Equation to work out the mass of 1 atom of an element: | (in kg)

- convert the Mr to kg mol^-1 by dividing by 1000 - then divide this by Avagadro's constant

# Molecular Ion Peaks for e- Impact 1) What is the peak with the largest m/z value called? 2) What is the peak with an m/z of 15 caused by?

1) 'Molecular Ion' peak 2) fragment cause by +CH3 ion

What is the m/z ratio of the molecular ion equal to?

the Mr of the whole molecule

Find the relative abundance of isotopes of Br2 | Exist as 79-Br and 81-Br isotopes. 50% abundance of each

1:2:1

1. Atomic Structure Flashcards

(45 cards)