Block 1 Flashcards
What are the 3 ways we look at a chemical reaction
- Observe
- Particulate (Think about the reaction and what’s happening at the molecular level)
- Symbolic
As chemists how should we view a chemical reaction
We should Particulate aka think about the reaction and what’s happening at the molecular level
Who is J.J Thomsom and what did he do?
He is a British Physicist from Cambridge. His research in cathode rays led to the discovery of the electron, and he pursued further innovations in atomic structure exploration.
What are canal rays?
Also called an anode ray, they are a beam of positive ions that is created by certain types of gas-discharge tubes
What are cathode rays?
A cathode ray is a beam of electrons in a vacuum tube traveling from the negatively charged electrode (cathode) at one end to the positively charged electrode (anode). They are also called electron beams.
What are Cathode ray tubes?
The cathode-ray tube is a vacuum tube that contains one or more electron guns and a phosphorescent screen and is used to display images. It modulates, accelerates, and deflects electron beam onto the screen to create the images..
Why is the Charge to Mass ratio (e/m) important?
Knowing the charge to mass ratio allows us to calculate the mass of the electron or proton by measuring charge effects. … Since the force on a charged particle is proportional to its charge, the deflection of a beam of charged particles will be the same for all particles with the same charge to mass ratio.
True or False. Electrons are lighter and smaller than atoms?
True
What are the three most common types of radioactive emissions?
Beta (B), Alpha (a), and Gamma (y) *Letters do not exactly represent the symbol for these radioactive emissions.
What charge do alpha particles have?
They have a positive charge
What charge do Beta particles have?
They can either have a negative or a positive charge?
What charge do Gamma particles have?
They have no charge
If you were to have 3 substances: paper, 0.5cm lead, and 10cm led in a row, out of the 3 most common types of radioactive emissions which could reach the 10cm led?
Gamma rays (y)
What is a geiger counter?
A Geiger counter is an instrument used for detecting radioactive emissions, most commonly beta particles and gamma rays.
What is a scintillation counter?
A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses.
What is the difference between the gieger counter and the scintillation counter?
The GM counter can detect all kinds of radiations such as alpha, beta and gamma rays, whereas the scintillation counter can detect only ionizing radiations.
What is the bohr model and is it used in modern times?
In atomic physics, the Rutherford–Bohr model or Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System. This model works easily in modern times with very simple atoms such as hydrogen although would be incorrect for other atoms these days and require another model.
What are ions?
Positively or negatively charged particles.
What is a mass spectrometer?
A mass spectrometer produces charged particles (ions) from the chemical substances that are to be analyzed. The mass spectrometer then uses electric and magnetic fields to measure the mass (“weight”) of the charged particles.
True or False Hydrogen does not have neutrons?
True.
Who discovered the neutron and in what year?
Chadwick (1932)
True or False neutron particles will have approximately the same mass as the proton of an atom.
True
How many atoms are in the human body?
7x10^27
Define atomic mass
Atomic mass is the mass of a single atom (its nuclei) of a chemical element. When calculating atomic mass the mass of electrons is negligible as its weight is too small to make a difference to our calculation.
What is the difference between the relative mass and the absolute mass?
The relative mass in the average atomic mass although the absolute mass is the exact sum of the number of protons and neutrons mass.
What is the difference between the relative charge and the absolute charge?
The relative charge in the average charge and the absolute charge is the exact sum of the charge.
What is the atomic mass number (atomic number) (A) also known as the mass number?
The total number of protons and neutrons (together known as nucleons) in an atomic nucleus.
Where would you find the atomic mass number on the periodic table for each element?
Below the element symbol.
What happens if you change the number of protons for an element?
Nothing happens to that element you are merely just changing which element you are looking at.
What happens if you change the number of neutrons for an element?
- The mass will change for that element (atom) 2. An isotope will form
What are isotopes?
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties
What is the relative atomic mass?
It is the ratio of the average mass per atom of an element from a given sample
What is the definition of a mole 2020?
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.02214076 × 10^23 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in mol−1, and is called the Avogadro number.
How to calculate atomic weight for multiple isotopes?
The atomic weight of multiple isotopes can be found by multiplying the abundance of an isotope of an element by the atomic mass of the element and then adding the results together. This equation can be used with elements with two or more isotopes: Example: Carbon-12: 0.9889 x 12.0000 = 11.8668. Carbon-13: 0.0111 x 13.0034 = 0.1443.
What is the avogadro constant (Na)?
Avogadro’s constant, is the number of particles found in one mole of a substance. 6.02214076 × 10^23.
How do you find the number of electrons in an atom?
This is the same as the number of protons in an atom which is the atomic number.
What are the 4 main elements in the human body?
O, C, H, and N
What percentage of the mass of a 60kg person is made up of Oxygen?
25.5%
What percentage of the mass of a 60kg person is made up of Carbon?
9.5%
What percentage of the mass of a 60kg person is made up of Hydrogen?
63%
What is Quantization?
Quantization is the concept that a physical quantity can have only certain discrete values.
How do atoms interact with the rest of the world?
Via the atom’s outer electrons
What are excited atoms?
An excited-state atom is an atom in which the total energy of the electrons can be lowered by transferring one or more electrons to different orbitals
What is spectroscopy?
Spectroscopy is a scientific measurement technique. It measures light that is emitted, absorbed, or scattered by materials and can be used to study, identify and quantify those materials.
What can the Emission and absorption of light tell us about a molecule?
It can tell us about the chemical(s) present and the amount present in a sample.
What are gas discharge tubes?
A gas discharge tube is usually a glass tube with two electrodes sealed through its walls. When a voltage is applied to the two electrodes and the pressure of the gas in the tube is reduced, eventually a pressure is reached at which a current flows, and the gas begins to glow.
What is electromagnetic radiation?
A kind of radiation including visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously.
What is the wavelength?
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave’s shape repeats
What is amplitude?
The maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position
What is visible light?
Visible light is a form of electromagnetic (EM) radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Generally, visible light is defined as the wavelengths that are visible to most human eyes.
What is ultraviolet radiation?
Ultraviolet light is a type of electromagnetic radiation that makes black-light posters glow, and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging to living tissue
What is the difference between visible light and ultraviolet radiation?
Ultraviolet (UV) light has shorter wavelengths than visible light. Though these UV waves are invisible to the human eye, some insects, like bumblebees, can see them! UV light also has more energy than visible light.
What is the speed of light?
The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its value is 3.00x10^8 m/s
True or False? Shorter wavelength = Higher frequency
True
What is the electromagnetic spectrum?
The range of wavelengths or frequencies over which electromagnetic radiation extends.
How do energy levels relate to the electromagnetic spectrum?
As you go further up the electromagnetic spectrum and the wavelengths become shorter energy should increase
What is the Balmer series?
The Balmer series, or Balmer lines in atomic physics, is one of a set of six named series describing the spectral line emissions of the hydrogen atom.
What is the lyman series?
The Lyman series is a hydrogen spectral series of transitions and resulting ultraviolet emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1, the lowest energy level of the electron.
What is the difference between Lyman and Balmer series?
The key difference between Lyman and Balmer series is that Lyman series forms when an excited electron reaches the n=1 energy level whereas Balmer series forms when an excited electron reaches the n=2 energy level
What is atomic absorption spectroscopy?
Atomic absorption spectroscopy (AAS) is based upon the principle that free atoms in the ground state can absorb light of a certain wavelength. Absorption for each element is specific, no other elements absorb this wavelength.
What is atomic emission spectroscopy?
Atomic emission spectra are unique spectra of light emitted by an element when electricity is run through it or when it is viewed through a prism. Because they are unique, they can act as an element s fingerprint
What are the 4 most common atoms in the human body?
OCHN (oxygen, carbon, hydrogen, nitrogen)
What percentage of the atoms in the human body are made up of oxygen?
25.5%
What percentage of the atoms in the human body are made up of carbon?
9.5%
What percentage of the atoms in the human body are made up of hydrogen?
63%
What percentage of the atoms in the human body are made up of nitrogen?
1.4%
What is calcium used for in the human body?
It is a major component of bone and is required in some enzymes.
What is phosphorus used for in the human body?
The synthesis of chemicals in the body and for energy transfer.
What is Sulfur used for in the human body?
It is required in proteins and other compounds
Where would you find the groups on the periodic table?
Going down (vertical)
Where do you find the periods in the periodic table?
Going across (horizontal)
Which chemistry is usually related with the transitional metals on the periodic table?
In-Organic chemistry
What types of elements are usually found to be in organic chemistry?
Non-metals
What colour goes hand in hand with organic chemistry?
White
What types of elements are usually found to be in inorganic chemistry?
Metals
What colour goes hand in hand with inorganic chemistry?
Lots of colours
What elements are halogens?
F Flourine, Cl Chlorine, Br Bromine, I Iodine, At Astaine, and Ts Tennessine
What bonds do halogens tend to form?
Ionic bonds
What are ionic compounds?
In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding
What are diatomic molecules?
Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements
What elements make ionic compounds?
Non metals and metals
What is ‘Ionic charge’?
ionic charge The electrical charge of an ion, created by the gain (negative charge) or loss (positive charge) of one or more electrons from an atom or group of atoms.
What is the octet rule?
The octet rule is a chemical rule of thumb that reflects the observation that elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
What is a cation?
A cation is an atom which has lost an electron giving the atom a positive charge.
What is an anion?
An anion is an atom that has gained an electron giving the atom a negative charge
What strength does Ionic bonding have? Weak, moderate or strong?
Strong bonding
True or False? only half of the periodic table consists of metals.
False, most of the elements on the periodic table are metals.
True or false? Metals gain electrons (become anions)
False, metals like to lose electrons (become cations)
When metals react with non metals what is the most common ionic compound that will be formed?
A salt
What is oxidation?
The loss of electrons
What is reduction?
The gain of electrons
What is a redox reaction?
Redox is a type of chemical reaction in which the oxidation states of atoms are changed. Redox reactions are characterized by the transfer of electrons between chemical species, most often with one species undergoing oxidation while another species undergoes reduction.
What does OIL RIG stand for?
Oxidation is loss, reduction is gain.
What are redox processes?
Redox is a type of chemical reaction in which the oxidation states of atoms are changed. Redox reactions are characterized by the transfer of electrons between chemical species, most often with one species undergoing oxidation while another species undergoes reduction
What is the standard form?
Standard Form. Standard form is a way of writing down very large or very small numbers easily. 103 = 1000, so 4 × 103 = 4000 . So 4000 can be written as 4 × 10³ .
Compare Valence electrons to Core electrons.
Core electrons are the electrons which sit close to the atom’s nucleus and the valence electrons are the electrons which sit in the outer shell and experience shielding.
What are lewis atomic symbols?
Lewis structures (also known as Lewis dot structures or electron dot structures) are diagrams that represent the valence electrons of atoms within a molecule.
What are double bonds?
A double bond in chemistry is a covalent bond between two atoms involving four bonding electrons instead of the usual two for single bonds. Double bonds occur most commonly between two carbon atoms, for example in alkenes
What is the atomic size trend on the periodic table?
Atomic size decreases across a period as the number of protons increase and the electrons are therefore more attracted to the nucleus. Atomic size increases down a group as there are more electron shells and shielding allows the valence electrons to creep further away from the nucleus.
What is the effective nuclear charge? Z*
The nuclear charge experiences by the outermost electrons in a multi electron atom.
How do you calculate the effective nuclear charge Z* of an atom?
“Z* = Z - S”, where Z* is the effective nuclear charge, Z is the number of protons in the nucleus, and S is the amount of inner electrons between that electron and its nucleus.
What trend does the effective nuclear charge have on the periodic table?
Effective nuclear charge will Increase across a period (due to increasing nuclear charge with no accompanying increase in shielding effect) and it will decrease down a group due to shielding.
What is shielding?
Electron shielding refers to the blocking of valence shell electron attraction by the nucleus due to the presence of inner-shell electrons.
What is nuclear charge?
The charge on the nucleus of an atom; controlled by the number of protons and electrons present in an atom.
Do elements in group 1 and 2 prefer to gain or lose electrons and are they metals or nonmetals?
They prefer to lose electrons and they are metals
Do elements in group 16 and 17 prefer to gain or lose electrons and are they metals or nonmetals?
They prefer to gain electrons and they are non metals
What happens when you react a metal with a non-metal?
You form a salt (ionic system)
What is Stoichiometry?
Stoichiometry is the study of the ratios between two or more substances undergoing a physical change or chemical change (chemical reaction).
What are Alkali metals?
The alkali metals consist of the chemical elements lithium, sodium, potassium, rubidium, caesium, and francium. Together with hydrogen they comprise group 1,
What are mono-cations?
A monocation is a cation formed by removal of a single electron from a neutral species.
What are Alkaline earth metals?
The alkaline earth metals are six chemical elements in group 2 of the periodic table.
What is ionisation energy?
The minimum amount of energy required to remove an electron from the outer shell
What is an ionic bond?
A type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
What is covalent bonding?
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. (When non-metals react together)
Why does Mg prefer to form Mg2+ rather than Mg3+?
Because forming Mg2+ gives the atom 8 valence electrons which is energy efficient although forming Mg3+ would give the atom an extra shell with 1 valence electron which has a high energy cost to the atom.
What is the lewis model?
Lewis structures, also called electron-dot structures or electron-dot diagrams, are diagrams that show the bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule. A Lewis structure can be drawn for any covalently-bonded molecule.
Which is stronger: Covalent bonding or Interactions between molecules?
Covalent bonding
What is good about covalent bonding?
The bonding is strong and directional.
What is electrostatic repulsion?
Electric repulsion is simply a phenom observed when like charges, for example to positive charges or two negative charges, are placed in close proximity to each other. According to basic electrical laws of physics, like charges repel each other, and unlike charges attract.
What is the Valence shell electron pair repulsion theory (VSEPR model) ?
Valence shell electron pair repulsion theory, or VSEPR theory, is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms
Can ionic bonds be polar or non polar
No as ionic bonds have complete separation of charge and the terms “polar” and “nonpolar” are usually applied to covalent bonds, where the molecule tends to have partial separation of charge.
What type of model does the VSEPR give?
A 3D model
What is the strategy of the VSEPR model?
- Draw a Lewis structure for the ion or molecule in question.
- Determine the number of electron groups around the central atom.
- Determine the number of lone pairs and the number of bonding pairs around the central atom, and use that to find the molecular geometry.
What is the bond angle for a tetrahedral shape?
109.5
What is the bond angle for a linear shape?
180
What is the bond angle for a trigonal planar shape?
120
What are dipoles?
In chemistry, a dipole usually refers to the separation of charges within a molecule between two covalently bonded atoms or atoms that share an ionic bond.
What are partial charges?
the partial charge on a particular atom in a polar molecule due to differences in electronegativity: for example if the charge (electron) is attracted more to O then O would have an s- partial charge.
Consider a water molecule H20, which atom would have which partial charge?
H- s+ charge
O- s- charge
What is electronegativity?
Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
What is the periodic trend of electronegativity?
Increases across a period and decreases down a group.
What group on the periodic table does not have any electronegativity and why?
The noble gasses group 18 as these atoms are content with their charge due to their full valence shell.
What are permanent dipoles?
Permanent dipoles. These occur when two atoms in a molecule have substantially different electronegativity: One atom attracts electrons more than another, becoming more negative, while the other atom becomes more positive. A molecule with a permanent dipole moment is called a polar molecule.
What is the direction of the molecular dipole?
The convention in chemistry is that the arrow representing the dipole moment goes from - to +
What are intermolecular forces?
Intermolecular forces (IMF) are the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between molecules and other types of neighbouring particles, e.g. atoms or ions.
Do all elements on the periodic table exist as solids at room temperature?
Most elements are solids, only 11 are gases and 2 are liquids Gas: (Nobel Gasses), H, N, O, F, CL. Liquid: Hg, Br
What are hydrophilic molecules?
A hydrophilic molecule or portion of a molecule is one whose interactions with water and other polar substances are more thermodynamically favorable than their interactions with oil or other hydrophobic solvents.
What are hydrophobic molecules?
To be hydrophobic means to fear water. In chemistry, it refers to the property of a substance to repel water. … Hydrophobic molecules tend to be non-polar molecules that group together to form micelles rather than be exposed to water. Hydrophobic molecules typically dissolve in non-polar solvents
What are intramolecular forces?
An intramolecular force is any force that binds together the atoms making up a molecule or compound
What is an example of an intermolecular force?
Weak bonding, Hydrogen bonding (Permanent dipoles)
What is an example of an intramolecular force?
Ionic and covalent bonding
Why do ionic salts dissolve in water?
• Water is polar
• Interacts strongly with itself and other polar
entities
• Good solvent to dissolve ionic molecules
(solute)
What is Stoichiometry?
Stoichiometry is the study of the ratios between two or more substances undergoing a physical change or chemical change (chemical reaction)
What is the first group on the periodic table called?
The alkali metals
What is the second group on the periodic table called?
The alkaline earth metals
What is the 17th group on the periodic table called?
The halogens
What is the the 18th group on the periodic table called?
The noble gasses
Which direction does the molecular dipole go in?
Towards the positively charged atom
