current Flashcards
All matter is made up of minute particles called what?
Atoms
Atoms are the basic building blocks of matter.
What holds the electron in orbit around the nucleus?
Force of attraction
This force is due to electromagnetic interactions.
The simplest atom is shown in Figure 1.1, which atom is it?
Hydrogen
Hydrogen is the lightest and most abundant element in the universe.
In all atoms, the nucleus contains particles that are called what?
Protons + neutrons
Protons are positively charged particles found in the nucleus.
What charge do protons have?
Positive
Protons carry a positive electrical charge.
Regarding protons and electrons, what is the basic principle of balance?
Same number of protons + electrons
Atoms are electrically neutral when they have equal numbers of protons and electrons.
Electrons are held in orbit about the nucleus by what force?
Force of attraction
This force is a result of the electromagnetic force between the positive nucleus and negative electrons.
What is the outer orbit or shell of an atom called?
Valence shell
The valence shell contains the outermost electrons that are involved in chemical bonding.
What is the electron called in the outer orbit or shell?
Valence electron
Valence electrons determine the chemical properties of an atom.
The simplest atom is the Hydrogen atom, how many electrons does it have?
One
Hydrogen has one electron in its outer shell.
If an electron is removed from an atom that has a weaker bond by an external force, the electron is known as?
Free electron
Free electrons can move freely in conductors and contribute to electric current.
What type of electrons flowing make an electrical current?
Free electrons
The flow of free electrons constitutes electric current.
In certain materials very little energy is required to force electrons out of orbit and enable current to flow, what are these materials called?
Conductors
Common conductors include metals like copper and aluminum.
In other materials the bond is between the nucleus and electrons is much stronger, and electrons are harder to dislodge, what are these materials called?
Insulators
Insulators include materials like rubber and glass, which prevent the flow of electric current.
Each electron forced out of orbit leaves its atom __________.
Positively charged
The atom becomes a positively charged ion after losing an electron.
If the polarity of a proton is positive (+ve) what is the polarity of an electron?
Negative
Electrons have a negative charge, which attracts them to protons.
Is an electron attracted to a negative charge?
False
Electrons are attracted to positive charges, not negative ones.
Electron flow is always from __________ to __________.
Negative to positive
This flow direction is conventional current flow.
What makes up an electric cell?
Two plates of different metal, electrolyte
The electrolyte facilitates chemical reactions that generate electricity.
What is the chemical reaction that takes place in a cell?
Electrolysis
Electrolysis involves the decomposition of a substance by passing an electric current through it.
If a conductor is connected to the two external plates of a battery what will happen?
The current will continue
The battery provides the necessary potential difference for current flow.
