Astronauts use "Astronomical Unit" to measure the distance between planets in our solar system "only". To measure long distances like between 2 galaxies, they use "light years". One Astronomical Unit = Average distance between sun and earth which is equal to 149.6 million kilometers. Ping me if you have any doubt.
The correct option is STRONTIUM.
Strontium is a group 2 element, that means it has two electrons in its outermost shell. This element will prefer to lose these two electrons in its outermost shell in order to attain the octet form, therefore, it will form electrovalent bond with non metals which it can donate two electrons to.
Answer:
Inert gases
Explanation:
Inert elements have a stable electron configuration meaning their shells/orbitals are full with their requisite number of electrons. Therefore, gaining or losing an electron would take high ionization energy. Therefore they are less likely to be involved in chemical reaction unless a high amount of energy is used. An example of an inert gas is Helium.
Answer:
propane -1 2 3 - trioic acid
Answer:
The Earth formed billions of years after the Universe formed
Explanation:
The "universe" is said to have been formed <em>billions of year ago</em> through an explosion. This was called the <em>"Big Bang Theory." </em>This lead to the<u> expansion of the universe</u> owing to its high temperature and density. After which, the universe cooled down. Galaxies and stars were then formed. Some of the stars died due to explosion, which then led to the <u>creation of planets</u>. Such formation of the planets happened around <u>4.5 billion years ago.</u> This is <em>9.3 billions of years later</em> than the universe was formed<em> (13.8 billions of years ago)</em>. So, this explains the answer.
