The Changing Nucleus Flashcards
What is ionic bonding?
When atoms give away electrons to another atom.
Atom- gains/loses electrons- becomes positively or negatively charged ion
What happens when an atom gives away an electron?
It becomes a “positive ion”- this is because it now has more protons than its electrons orbiting the nucleus
Name several features of ionic compounds
- Overall charge of zero
- Include both metals + non-metals
- Has positive ions (cations) and negative ions (anions)
- Has strong ionic bonds
- Has 3 dimensional lattice of positive and negative ions
- Are solid at room temperature
- Has both high melting and boiling points
- Conduct electricity
- Dissolve in water
- Are brittle
Name several features of covalent compounds
- Are only non-metals
- Have molecules (group of atoms joined by covalent bonds)
- Molecules have weak bonds
- Are liquid or gas at room temperature (low melting and boiling points)
- Do not conduct electricity
- Not all these substances dissolve in water
- Are soft
What is atomic number?
Number of protons the element has in its atom
What is mass number?
Sum of the number of protons and neutrons in an atom
What is radioactive decay?
When an unstable atomic nucleus loses energy in the form of emitted particles or electromagnetic waves (aka radiation)
*Think-
Unstable atomic nucleus- loses energy (as emitted particles or electromagnetic waves)- forms radiation.
What are isotopes?
Atoms of the same element (therefore having the same number of protons) which differ in the number of neutrons in their nucleus
What is radioactivity?
The energy or particles from the nucleus of unstable atoms
What is covalent bonding?
Simply- sharing of electrons
What is the difference between atoms and molecules?
Atoms- single neutral particles
eg. Mg
Molecules- 2 or more atoms bonded together
eg. O2, Co2, NaCl
Elements vs compounds
Elements- only one type of atom
Compounds- 2 or more different types of atoms
Define the term ‘half-life’
The time taken for a sample of a radioactive substance to decrease its radioactivity by a half
What is the nuclear symbol for alpha particles?
4/2 α (has 2 protons and 2 neutrons)
What is the nuclear symbol for beta particles?
0/-1 B (mass is so small it can be considered to be zero, charge is -1 which is written as its mass number)
What is a nuclear reaction?
One that involves a change in the number of protons and/or neutrons in the nucleus.
- always involves release of radiation
- whenever nuclear reaction occurs, a new element is formed
- The element that is formed depends on the type of radioactive particle that is released
What happens when atoms have too many neutrons in its nucleus?
They often release beta particles during radioactive decay.
During beta decay, neutron -changes into a proton and an electron- proton remains in the nucleus- electron (beta particle) is released.
What are benefits of nuclear energy?
No Co2 emitted and very useful for medical imaging and cancer treatment
What problems are associated with nuclear energy?
Radioactive waste product can remain hazardous for 60,000 years, an accident can be dangerous
