Answer:
Electrons have negative charge.
<span><em>Answer:</em>
A strontium-90 atom that has a lost two electrons has <u>38</u> protons, <u>52</u> neutrons, and <u>36</u> electrons.
<em>Explanation:
</em>Atomic number<em> of </em>Strontium (Sr) is 38.
<em>Atomic number = number of protons
</em>Hence, Strontium has 38 protons.
If the element is in neutral state,
number of protons = number of electrons.
Then, neutral Strontium atom should have 38 electrons.
But the question says Sr has lost 2 electrons. Hence, number of electrons should be 38 - 2 = 36.
Mass number = number of protons + number of neutrons.
The given mass number is 90. Hence, number of neutrons should be 90 - 38 = 52.</span>
1. The answer is; C
The geosphere is made up of the physical rocks (composed of metals and minerals) and magma in the different layers. These densities of these rocks surpass those of other spheres such as the atmosphere and hydrosphere.
2. The answer is; B
Destructive forces break down land. Weathering and erosion are categorized as slow destructive forces because they take many years for their effect to be perceptible to the human's scale. Quick destructive forces are forces such as earthquakes and tsunamis.
3. The answer is; B
The atmosphere on earth is mainly composed of molecular nitrogen at 78%. Oxygen takes up 21% and other gases found in the atmosphere are hydrogen, carbon dioxide,ozone, dust, and water vapor at 1%.
4. The answers that apply are ; A & B
The formula for gravity force is given by the equation.; F(gravity) = (G*m1*m2)/d^2 where G is the gravitational constant, m1 and m2 are the masses of the two objects, and d is the distance between them.
5. The answer is; C
The force of inertia is due to their celestial mass. The larger the mass the higher the inertia. Inertia is the tendency of a moving object to maintain a straight path without an external force applied to it. This, therefore, prevents the moon from being pulled into collision with the earth. Gravity, on the other hand, prevents the moon from flying out of its orbit and away into space.
At 40 degrees Celsius, approximately 78 grams of potassium bromide can be dissolved.
