I think the first question is talking about the ionic compound Sodium sulfide and it’s formula is Na2S.
And for the second question, i’m pretty sure it’d be a positive charge
Answer:
Two oxygen atoms
Explanation:
The majority of the oxygen in the air in our atmosphere consists of molecular oxygen (
), which consists of 2 atoms of oxygen, since free oxygen mainly form covalent bonds with other atoms of oxygen.
A small fraction of the oxygen, however, in the ozone form, which consists of 3 atoms of oxygen bond together (
).
Answer:
B) changing position
Explanation:
When a ball bounces to the ground it hits the ground with some energy. The amount of energy with which it hits the ground is kinetic energy. When it comes in the contact with the ground kinetic energy gets converted into potential energy. This potential energy again gets converted into kinetic energy and balls moves again from the ground and bounces multiple times. So, due to multiple bounce the position of the ball changes.
Thus, When bouncing a ball, the bouncing motion results in the ball changing position.
<h2>
Answer: Invariance of the speed of light in vacuum </h2>
Special relativity was proposed on 1905 by Einstein, who developed his theory based on the following two postulates:
<em>1. The laws of physics are the same in all inertial systems. There is no preferential system. </em>
<em>2. The speed of light in vacuum has the same value for all inertial systems. </em>
<em></em>
Focusing on the first postulate, it can be affirmed that any measurement on a body is made with reference to the system in which it is being measured.
In addition, it deals with the <u>dilation of time</u> stating that <u>time passes at different rates in regions of different gravitational potential</u>. That is, the greater the local distortion of space-time due to gravity, the slower the time passes.
On the other hand, following what relativity establishes, bodies within a gravitational field follow a curved space path.
Answer: C. unknown element he predicted would have properties similar to those of aluminum.
Explanation: Mendeleev arranged the elements in order of increasing atomic masses. He left spaces for the elements that were predicted to exist, but were not discovered.
One space was left below Aluminum where an element of mass 70 was predicted to exist with properties similar to Aluminum. It was referred to as eka-Aluminum.
Later it was named as gallium.
