Mystery Solution II Flashcards
What makes the atom unstable?
When atoms do not have full outer shells of electrons
What occurs when atoms are unstable?
- Atoms react in a way to try to fill their outer shell
- Through transferring electrons to other atoms by giving up or gaining electrons to complete their outer shell (ionic bonding)
- Or by sharing electrons with other atoms (covalent bonding)
What type of element usually form positive ions?
Metallic elements
What type of atom usually form negative ions?
Non-metallic elements
What are radicals?
When group of atoms are chemically bounded carry a net charge and behave like a single ion
Does elements with 4 outer- shell electrons form ions?
No
An atom with 7 outer- ring electrons have a valence of -1?
Yes
What are valence electrons?
Electrons in the outer shell of an atom
What is it when its soluble?
Is when a solid dissolves in a liquid. The resulting solution being clear
What is it when its insoluble (precipitate)?
Is when a solid does not dissolve in a liquid. With the resulting solution being cloudy and with the solid dispensed or floating.
Why do isotopes have the same chemical properties?
Because they all have the same number of protons and valence electrons hence electron configuration.
What is an isotope that is radioactive?
Radioisotope
What happens when the number of neutrons is greater than the number of protons?
The nucleus becomes unstable and break up. When this happens a nuclear reaction occurs and the isotopes is said to be radioactive.
Who was the early pioneers in radioactivity?
Rutherford: discovers alpha and beta rays
Roentgen: discover x-rays
The Curries: discovers of radium and polonium
What does it mean by radioactivity?
Radioactivity is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves.
Basically when an unstable nucleus releases energy to become stable
What does alpha, beta, gamma releases?
- Alpha releases alpha particles, neutrons and protons from a nucleus
- Beta releases electrons (beta particles)
- Gamma releases photons, short- wave electromagnetic radiation
What is the half- life of a radioactive substance?
Is the time required for one half of it to decay
What are sources of radioactivity?
- Primordial: from before the creation of the Earth
- Cosmogenic: formed as a result of cosmic ray interactions
- Human produced: enhanced or formed due to human actions
Where are naturally occurring sources of radioactivity?
- Carbon- 14: found in plants and animal tissue
- Potassium- 40: found in minerals and in plants
Where are man-made sources of radioactivity used in?
- Certain consumer products e.g. smoke detectors
- Medical purposes with the use of radioactive isotopes
What are catalysts?
They speed up reaction and decreases activational energy e.g. enzymes
Though is not used up
What phenomenon occurs when a metal ion is heated?
When a metal ion is heated, the electrons get enough energy to jump higher away from the nucleus. And when they fall back, becoming closer to the nucleus they give off this extra energy as light.
What is an element?
Substances that contain one type of atom and are pure substances
What is a compound?
When different elements are chemically combined together
