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Questions and Answers
Which trace element is commonly associated with the geographical origin of bone composition?
Which trace element is commonly associated with the geographical origin of bone composition?
- Barium
- Zinc
- Iron
- Strontium (correct)
What role does diet play in the composition of bones regarding trace elements?
What role does diet play in the composition of bones regarding trace elements?
- Diet determines the incorporation of metals into bone structure. (correct)
- Diet selectively removes trace elements from bones.
- Diet only influences calcium levels in bones.
- Diet has no impact on bone composition.
Which of the following metals is NOT mentioned as being part of bone chemistry?
Which of the following metals is NOT mentioned as being part of bone chemistry?
- Copper
- Strontium
- Lead
- Nickel (correct)
In terms of bone composition, what does the relative abundance of trace elements suggest about a person’s lifestyle?
In terms of bone composition, what does the relative abundance of trace elements suggest about a person’s lifestyle?
Which statement best describes how the presence of metals like copper and lead can be interpreted?
Which statement best describes how the presence of metals like copper and lead can be interpreted?
What is the range of antimony (Sb) content in bullets of this type?
What is the range of antimony (Sb) content in bullets of this type?
What likely indicates the presence of a single gunman in the analysis of bullets?
What likely indicates the presence of a single gunman in the analysis of bullets?
What significant finding was indicated by the findings in the boy’s body discovered in the Thames?
What significant finding was indicated by the findings in the boy’s body discovered in the Thames?
What substance was found in the boy’s stomach that is linked to West African black magic?
What substance was found in the boy’s stomach that is linked to West African black magic?
Which element is NOT part of the composition of bone?
Which element is NOT part of the composition of bone?
What does the presence of pollen found in the boy's stomach suggest?
What does the presence of pollen found in the boy's stomach suggest?
What does the analysis of bullet fragments reveal about silver (Ag) concentration?
What does the analysis of bullet fragments reveal about silver (Ag) concentration?
What does the specific analysis of weapons suggest about the crime scene?
What does the specific analysis of weapons suggest about the crime scene?
What effect does introducing a metal salt into a flame have on its color?
What effect does introducing a metal salt into a flame have on its color?
Which color does sodium emit when its electrons transition back to the ground state?
Which color does sodium emit when its electrons transition back to the ground state?
What is the main principle behind flame tests for identifying metals?
What is the main principle behind flame tests for identifying metals?
What is indicated by the flame turning a specific color during a flame test?
What is indicated by the flame turning a specific color during a flame test?
What is the purpose of a flame photometer in the context of flame tests?
What is the purpose of a flame photometer in the context of flame tests?
Which of the following colors is NOT produced by the listed metals in flame tests?
Which of the following colors is NOT produced by the listed metals in flame tests?
What distinguishes qualitative analysis from quantitative analysis in flame testing?
What distinguishes qualitative analysis from quantitative analysis in flame testing?
What physical property of the emitted light is crucial for flame tests?
What physical property of the emitted light is crucial for flame tests?
What distinguishes a chemical element from a compound?
What distinguishes a chemical element from a compound?
Which of the following statements about elements is incorrect?
Which of the following statements about elements is incorrect?
Which of these elements is not a basic building block of the human body?
Which of these elements is not a basic building block of the human body?
What is the primary purpose of emission and absorption spectroscopy?
What is the primary purpose of emission and absorption spectroscopy?
Which of the following compounds contains carbon?
Which of the following compounds contains carbon?
What does the periodic table organize?
What does the periodic table organize?
The formula CO2 represents what type of substance?
The formula CO2 represents what type of substance?
In the context of forensic science, what type of analysis is primarily concerned with determining the elements present in a sample?
In the context of forensic science, what type of analysis is primarily concerned with determining the elements present in a sample?
What happens to electrons when they absorb energy?
What happens to electrons when they absorb energy?
What is indicated by the frequency of electromagnetic radiation emitted or absorbed by an electron?
What is indicated by the frequency of electromagnetic radiation emitted or absorbed by an electron?
How are the allowed energy levels in an atom best represented?
How are the allowed energy levels in an atom best represented?
What occurs when an electron drops to a lower energy level?
What occurs when an electron drops to a lower energy level?
What does the de Broglie equation express?
What does the de Broglie equation express?
What is a characteristic feature of the emission spectrum obtained from an element?
What is a characteristic feature of the emission spectrum obtained from an element?
How does absorption spectroscopy help in identifying elements?
How does absorption spectroscopy help in identifying elements?
When an atom is in the excited state, what must happen for it to return to the ground state?
When an atom is in the excited state, what must happen for it to return to the ground state?
What kind of radiation is absorbed when electrons jump to a higher energy level?
What kind of radiation is absorbed when electrons jump to a higher energy level?
What distinguishes the different patterns in the spectral lines of elements?
What distinguishes the different patterns in the spectral lines of elements?
What is the relationship between energy absorbed and emitted by an electron?
What is the relationship between energy absorbed and emitted by an electron?
What role does a prism play in spectroscopy?
What role does a prism play in spectroscopy?
What will happen if the energy supplied to an electron does not match the required energy gap?
What will happen if the energy supplied to an electron does not match the required energy gap?
In electronic transitions, which of the following is true about the ground state?
In electronic transitions, which of the following is true about the ground state?
Flashcards
Element
Element
A fundamental substance that cannot be broken down into simpler substances by chemical means.
Compound
Compound
A substance formed by the chemical combination of two or more different elements in a fixed ratio.
Periodic Table
Periodic Table
A table that organizes elements based on their chemical properties.
Atomic Structure
Atomic Structure
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Ground State
Ground State
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Excited State
Excited State
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Spectroscopy
Spectroscopy
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Absorption Spectroscopy
Absorption Spectroscopy
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Emission Spectroscopy
Emission Spectroscopy
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Flame Test
Flame Test
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Trace Elements
Trace Elements
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Energy Levels
Energy Levels
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Electromagnetic Radiation
Electromagnetic Radiation
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Study Notes
Elements and Compounds
- Elements are the fundamental building blocks of matter, substances that cannot be transformed into other substances
- Elements combine to form compounds: multiple elements joined together
- 93 natural elements exist and more are created artificially
- Elements cannot be created or destroyed, only rearranged into different compounds
- Examples of elements in everyday life include: Carbon (C), Hydrogen (H), Oxygen (O), Iron (Fe), Zinc (Zn), Uranium (U), Iridium (Ir), Samarium (Sm), Gadolinium (Gd), Krypton (Kr), Thallium (Tl)
- Examples of elements in the human body include: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Sulfur (S), Calcium (Ca), Sodium (Na), Potassium (K), Iron (Fe), and trace amounts of gold (Au) and mercury (Hg) in dental fillings
The Periodic Table
- Organizes elements based on their chemical properties
- Developed by Dmitri Mendeleev, a Russian chemist
Atomic Structure
- Niels Bohr proposed electrons are only allowed to occupy specific energy levels around the nucleus
- An atom's ground state refers to its lowest energy level
- An atom's excited state refers to when electrons absorb electromagnetic radiation and jump to higher energy levels
- When an electron drops back to a lower energy level, it releases energy in the form of electromagnetic radiation (light)
- The frequency of the emitted or absorbed electromagnetic radiation corresponds to the energy difference between the energy levels
- Each element has its own unique set of energy levels and thus a distinct energy level pattern
- Energy levels are not evenly spaced, like the rungs of a ladder, but rather have a specific energy difference between each level
Spectroscopy
- Spectroscopic techniques use electromagnetic radiation to identify the elements present in a sample and to measure their concentration
- The different ways in which atoms interact with electromagnetic radiation form the basis for several important spectroscopic techniques
Absorption Spectroscopy
- Atoms absorb specific frequencies of light corresponding to energy differences between their energy levels
- When atoms absorb light, electrons are promoted to higher energy levels
- The absorption spectrum provides a unique fingerprint of each element
- Absorption spectroscopy can be used to identify the presence and concentration of elements in a sample
Emission Spectroscopy
- Atoms emit light when excited electrons drop back to lower energy levels (ground state)
- The emitted light has specific frequencies corresponding to energy differences between the energy levels
- Emission spectroscopy can be used to identify elements based on the frequencies of light they emit
- The intensity of the emitted light is proportional to the concentration of the element
Flame Tests for Metals
- Flame tests use a flame's heat to excite electrons in metal atoms, causing them to emit visible light
- The color of the light emitted is characteristic of the metal
- Flame tests are qualitative, they identify which element is present, but not their exact quantity
- Flame photometers quantify the amount of a particular element present by measuring the intensity of light emitted at a specific frequency
Case Studies
- Napoleon's Death: Analysis of hair samples indicated high levels of arsenic, raising questions about the cause of his death
- The Kennedy Assassination: analysis of gunshot residue on clothing using spectroscopy helped determine the number of bullets fired and their origin
- Adam's Body: Analysis of the body's contents, including pollen, clay, and calabar beans, helped trace the victim's origin and possible cause of death
- Bullet Analysis: Analysis of trace elements (Ag, Sb) in bullet fragments can link different bullets to the same gun
Understanding Trace Elements
- The relative abundance of trace elements in bone can indicate a person's geographical origin, due to their presence in the diet and environment
- Individuals who live in areas with unique mineral compositions in their soil and food will reflect those concentrations in their bones
- Trace element analysis can provide valuable information for identifying the geographical origin of an individual, even if they have moved to a different location
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