📚🔥Chemistry 1.2 -basic Ideas About Atoms Flashcards
What is an atom?
A nucleus made up of positively charged protons and uncharged neutrons surrounded by a shell of negativity charged electrons
What has the same value as the proton number?
The electron number
What is the atomic number, what has the same value as the atomic number?
Atomic number is the bottom number and it shows the value of protons and electrons
What is the mass number and what can it calculate?
The mass number is the top Number and it is the total number of protons and neutrons in the nucleus
What is an isotope?
The same element which has the same number of protons but a different number of neutrons
When is a positive ion formed?
When an atom loses one of more electrons
When is a negative ion formed?
When an atom gains one or more electrons
Give an equation to show the formation of a positive ion
K—> K* + e-
Give an equation to show the formation of a negative ion
F + e- —> F-
What is the nature of alpha, beta and gamma radiation?
Alpha = 2 protons and 2 electrons Beta= fast moving electrons Gamma= High energy electromagnetic radiation
Name the penetrating power of alpha, beta and gamma radiation
Alpha= least penetrating, stopped by a piece of paper Beta= stopped by thin sheet of metal (0.5cm of aluminium) Gamma= most penetrating, more than 2cm of lead
Name the nature of alpha, beta and gamma radiation in an electric field
Alpha= attracted to negative plate Beta= attracted to positive plate Gamma= no effect
Name the nature of alpha, beta and gamma radiation in a magnetic field
Alpha= deflected in a certain direction Beta= deflected in opposite direction Gamma= no effect
What happens to the mass and atomic number during an alpha decay equation
Mass = decreases by 4 Atomic = decreases by 2
What happens to the mass and atomic number during a beta decay equation
Mass = unchanged Atomic = increases by 1
What happens to the mass and atomic number during electron capture?
Mass= unchanged Atomic= decreases by 1
What is half life?
The time taken for one half of all nuclei in a radioisotope to decay or the time taken for the radioactivity of a radioisotope fo fall to half of its initial value
What are the consequences of radioactivity on living cells?
High energy radioactive emissions break chemical bonds in the cell molecules causing changes in the DNA resulting in mutations and the formations of cancerous cells at lower doses and death at higher doses
Why is colbalt-60 a benefit of radioactivity
The high energy gamma radiation is used to kill cancer cells and prevent malignant tumors forming
Why is Iodine 131 a benefit of radioactivity in medicine?
Treats patients with defective thyroid glands, it acts as a teacher to study uptake if iondine in the gland
Why is technetium 99 a benefit of radioactivity in medicine?
Used as a trader to label a molecule that is taken up by the tissue to be studied
Name another used of radioisotopes?
Used in radio dating
Explain the process of radiodating
-living organisms absorb carbon that includes a small proportion of carbon 14, when the organism dies no more absorption of carbon 14 occurs and present carbon 14 decays, the rate of decay decreases over years and can be used to measure the age of organisms
How is radiation used in analysis?
It can be used to monitor the thickness of metal strip, a radioactive source (beta emission) is mounted in one side of the metal with a detector on the other, if the amount of radiation reaching the detector increases the detector operates a mechanism for moving the rollers apart and vice versa
