A compound machine is that which is composed of two or more simple machines. Simple machines come in 6 basic types: (1) wheel and axle, (2) inclined plane, (3) wedge, (4) pulley, (5) screw, and (6) lever. Among the choices given above, the compound machine is the can opener for it is a combination of a wedge and a lever.
Answer: A
The protons in the nucleus repel each other
Explanation:
the number of protons inside a nucleus increases the electrostatic repulsion between protons increase reducing the binding energy. Thus the electrostatic force determines the stability of a nuclear configuration
A hidden virus hides out inside the host cell for a time before it becomes active. An example of this is a cold sore on your lip.
Answer: A) Na+ and O2-
Explanation:
To know the electronic configuration, one has to determine the numbers of electrons present in each atom.
Na+ means a sodium atom that has lost one valence electron. A Sodium atom initially has 11 electrons, but having lost an electron making it 10 electrons remaining with electron configuration of 1s2 2s2 2p6.
O2- means oxygen atom that has gained two valence electrons. An oxygen atom initially has 8 electrons, having gained two electrons makes it 10 electrons with electron configuration of 1s2 2s2 2p6. same as Na+
The purpose of gaining or losing electrons is to attain a stable duplet or octet structure.
I think it's Potassium iodide because it has the highest solubility at 25°C.
