Gizmo Warm-up Just like students sharing markers, atoms sometimes share or swap electrons. By doing this, atoms form bonds. The Ionic Bonds Gizmo allows you to explore how ionic bonds form. To begin, check that Sodium (Na) and Chlorine (Cl) are selected from the menus at right. Click Play ( ) to see electrons orbiting the nucleus of each atom. (Note: These atom models are simplified and not meant to be realistic.) 1. Each atom consists of a central nucleus and several shells that contain electrons. The outermost electrons are called valence electrons. How many valence electrons does each atom have

Sodium element has 1 valence electron and chlorine element has 7 valence electrons.

Explanation:

Valence electrons are defined as the electrons that are present in the outermost shell.

An ionic compound is formed when the complete transfer of electrons takes place from one element (usually metals) to another element (usually non-metals).

To know this, we need to write the electronic configuration of each element.

Sodium is the 11th element of the periodic table and has an electronic configuration of

It has 1 valence electron

Chlorine is the 17th element of the periodic table and has an electronic configuration of

It has 7 valence electrons

Hence, sodium element has 1 valence electron and chlorine element has 7 valence electrons.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol