Answer:
Retrograde Motion
Explanation:
The theory that the earth revolves around the Sun is called the heliocentric theory, helio meaning 'sun' and centric meaning 'in the center.
' This theory was developed in parts by different astronomers over many years, namely Aristarchus, Copernicus, Kepler, and Galileo.
The reaction from society at the time was that the heliocentric theory was not even worth talking about.
Everyone had evidence to prove that the Earth was the center because if the sun started at one point in the morning and ended at another at night, it was common sense that we were obviously the center.
Copernicus heliocentric theory or it is also named as Sun-centred theory had accepted by Galileo.
The geocentric model is also known as geocentrism.
valence electrons are the number of electrons in the outermost shell.
electron configuration is where the electrons are arranged in ascending order of energy shells
the electron configurations for the elements given are as follows
C - 2,4
Al - 2,8,3
Na - 2,8,1
Ca - 2,8,8,2
from the given elements, Aluminium has 3 electrons in its outermost shell.
answer is Aluminium
The molecular equation :
MgI₂(aq) + Pb(NO₃)₂(aq) → Mg(NO₃)₂(aq) + PbI₂(s)
The net ionic equations
Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s)
<h3>Further explanation</h3>
Given
Word equation
Required
The molecular equations and the net ionic equations
Solution
The chemical equation can be expressed in terms of:
- word equation
- skeleton equation
- balanced equation
The equation of a chemical reaction can be expressed in the equation of the ions
When a spectator ions are removed, the ionic equation is called the net ionic equation
A molecular equation is a chemical equation that has been balanced and is written in molecular (not ionic) form
The molecular equation :
MgI₂(aq) + Pb(NO₃)₂(aq) → Mg(NO₃)₂(aq) + PbI₂(s)
the ionic equation :
Mg²⁺ +2I⁻ + Pb²⁺ + 2NO₃⁻ → Mg²⁺ + 2NO₃⁻ + PbI₂
the net ionic equations
Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s)
Do you mean; " A blank is a substance that is made by combining two elements?" (I'm not sure if substances is the right term)
If so then the blank is a compound.