Selenium has 36 electrons34(atomic number) + 2(amount of electrons gained in the <span>ion, has a 2- charge) = 36
</span>To identify the number of electrons an element has, all you need is a periodic table. Identify the atomic number (the smallest of the 2 numbers in the box). That number will be the number of protons which is also the number of electrons.
*number Atoms of all elements are made up of three primary particles: protons, neutrons, and electrons. The "sub-atomic" particles each have specific properties that such as size, electrical charge, etc. that are crucial for the stability of the atom. The particles break down like this: Particle Relative size Charge Location How to determine
Proton 1 + in the nucleus # of protons= element's atomic # (use periodic table)
Electron 0 - outside nucleus # of electrons=# of protons(in neutral, "normal" atom)
Neutron 1 0 in the nucleus Must be told or given (ie. can vary--isotopes--
for small elements most common form often
consists of isotope where #protons=#neutrons) Aluminum has 13 electrons because it needs 13 negative charges to balance the 13 postively-charged protons (which is what the periodic table told us it contains). This will make the Aluminum atom electrically neutral.
To determine the number of hair dryers that can be plugged in to a circuit, our basis is the maximum threshold of the current. The current which measures 12 Amperes. This current already incorporates the safety factor that is important in industrial setting.
The voltage and the current can be related to the power by the equation:
P = I*V, where I is the current in Amperes and V is the voltage in volts
Solving for the total power:
P = 12 A * 110 V
P = 1,320 Watts
Since the power rating of each hair dryer is 350 W, we divide this to the total power to determine the capacity.
Number of hair dryers = 1,320 Watts/350 Watts per hair dryer
Number of hair dryers = 3.77
In this case, we cannot round off to 4 because this would already exceed the maximum power capacity. Therefore, the total number of hair dryers allowable is 3.
The formula for maximum distance is
X = (V^2 / g) * sin (2 * theta)
10 = (V^2 / 9.8) * sin (2 * 20)
10 = (V^2 / 9.0) * sin(40)
10 = (V^2 / 9.8) * 0.324
v^2 = (10 / 0.324) * 9.8
V^2 = 302.47
v = 17.39 meters/sec (takeoff speed)
The horizontal speed is = Takeoff Speed * Cos(20) = 17.39 * 0.910 = 16.341 meters / sec
You should ALWAYS wear lab coats and safety goggles because if anything gets in your eye that will be bad.You should always wear sneakers.If any chemical falls on your open toes then that can hurt you and effect you in a lot of ways.Some labs have this rule,you are not aloud to eat or drink in lab.Hope this helps!
There would be no light at night foe nocturnal animals
is the charge density
is the vacuum permittivity